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• Ubuntu 12.04 KVM running Ubuntu 12.04 with linux-image-virtual crash on boot

  - by D.Mill

  One of my VMs is stuck on "pause" in virsh. If I destroy and restart it, it will go to pause after a bit of time as "running". I can at best enter my username at login if I'm quick but it'll then shutdown. I don't know where to start with this so any help would be great!! I can access the VMs files via guestfish. the kern.log and syslog don't populate new lines. This is the last input I get from kern.log: Dec 13 11:21:08 soft201 kernel: imklog 5.8.6, log source = /proc/kmsg started. Dec 13 11:21:08 soft201 kernel: [ 0.000000] Initializing cgroup subsys cpuset Dec 13 11:21:08 soft201 kernel: [ 0.000000] Initializing cgroup subsys cpu Dec 13 11:21:08 soft201 kernel: [ 0.000000] Linux version 3.2.0-34-virtual (buildd@allspice) (gcc version 4.6.3 (Ubuntu/Linaro 4.6.3-1ubuntu5) ) #53-Ubuntu SMP Thu Nov 15 11:08:40 UTC 2012 (Ubuntu 3.2.0-34.53-virtual 3.2.33) Dec 13 11:21:08 soft201 kernel: [ 0.000000] Command line: root=UUID=61d48b48-a06a-48fb-842e-b38014086a93 ro quiet splash Dec 13 11:21:08 soft201 kernel: [ 0.000000] KERNEL supported cpus: Dec 13 11:21:08 soft201 kernel: [ 0.000000] Intel GenuineIntel Dec 13 11:21:08 soft201 kernel: [ 0.000000] AMD AuthenticAMD Dec 13 11:21:08 soft201 kernel: [ 0.000000] Centaur CentaurHauls Dec 13 11:21:08 soft201 kernel: [ 0.000000] BIOS-provided physical RAM map: Dec 13 11:21:08 soft201 kernel: [ 0.000000] BIOS-e820: 00000000000f0000 - 0000000000100000 (reserved) Dec 13 11:21:08 soft201 kernel: [ 0.000000] BIOS-e820: 0000000000100000 - 00000000dfffc000 (usable) Dec 13 11:21:08 soft201 kernel: [ 0.000000] BIOS-e820: 00000000dfffc000 - 00000000e0000000 (reserved) Dec 13 11:21:08 soft201 kernel: [ 0.000000] BIOS-e820: 00000000feffc000 - 00000000ff000000 (reserved) Dec 13 11:21:08 soft201 kernel: [ 0.000000] BIOS-e820: 00000000fffc0000 - 0000000100000000 (reserved) Dec 13 11:21:08 soft201 kernel: [ 0.000000] BIOS-e820: 0000000100000000 - 0000000a20000000 (usable) Dec 13 11:21:08 soft201 kernel: [ 0.000000] NX (Execute Disable) protection: active Dec 13 11:21:08 soft201 kernel: [ 0.000000] DMI 2.4 present. Dec 13 11:21:08 soft201 kernel: [ 0.000000] DMI: Bochs Bochs, BIOS Bochs 01/01/2007 Dec 13 11:21:08 soft201 kernel: [ 0.000000] e820 update range: 0000000000000000 - 0000000000010000 (usable) ==> (reserved) Dec 13 11:21:08 soft201 kernel: [ 0.000000] e820 remove range: 00000000000a0000 - 0000000000100000 (usable) Dec 13 As you can see the last line gets cut off. I don't even know if this is that relevant. dmesg logs are empty. The qemu log for the VM returns this: 2012-12-13 12:29:47.584+0000: starting up LC_ALL=C PATH=/usr/local/sbin:/usr/local/bin:/usr/bin:/usr/sbin:/sbin:/bin QEMU_AUDIO_DRV=none /usr/bin/kvm -S -M pc-1.0 -enable-kvm -m 40960 -smp 14,sockets=14,cores=1,threads=1 -name numerink201 -uuid f4a889ed-a089-05d0-cc9d-9825ab1faeba -nodefconfig -nodefaults -chardev socket,id=charmonitor,path=/var/lib/libvirt/qemu/numerink201.monitor,server,nowait -mon chardev=charmonitor,id=monitor,mode=control -rtc base=utc -no-shutdown -drive file=/var/lib/libvirt/images/client.soft.fr/tmpcZAD9U.qcow2,if=none,id=drive-ide0-0-0,format=qcow2 -device ide-drive,bus=ide.0,unit=0,drive=drive-ide0-0-0,id=ide0-0-0,bootindex=1 -fsdev local,security_model=none,id=fsdev-fs0,path=/home/shared_folders/soft201 -device virtio-9p-pci,id=fs0,fsdev=fsdev-fs0,mount_tag=hostshare,bus=pci.0,addr=0x5 -netdev tap,fd=18,id=hostnet0 -device virtio-net-pci,netdev=hostnet0,id=net0,mac=02:00:00:1d:b9:e7,bus=pci.0,addr=0x3 -chardev pty,id=charserial0 -device isa-serial,chardev=charserial0,id=serial0 -usb -vnc 127.0.0.1:0 -vga cirrus -device virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x4 char device redirected to /dev/pts/3 qemu: terminating on signal 15 from pid 28248 2012-12-13 12:30:14.455+0000: shutting down I've added more logging, libvirt.log gives me this: 2012-12-13 13:24:38.525+0000: 27694: info : libvirt version: 0.9.8 2012-12-13 13:24:38.525+0000: 27694: error : virExecWithHook:328 : Cannot find 'pm-is-supported' in path: No such file or directory 2012-12-13 13:24:38.525+0000: 27694: warning : qemuCapsInit:856 : Failed to get host power management capabilities 2012-12-13 13:24:39.865+0000: 27694: error : virExecWithHook:328 : Cannot find 'pm-is-supported' in path: No such file or directory 2012-12-13 13:24:39.865+0000: 27694: warning : lxcCapsInit:77 : Failed to get host power management capabilities 2012-12-13 13:24:39.866+0000: 27694: error : virExecWithHook:328 : Cannot find 'pm-is-supported' in path: No such file or directory 2012-12-13 13:24:39.866+0000: 27694: warning : umlCapsInit:87 : Failed to get host power management capabilities I don't really know where to go from here. I'll post whatever info you require

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• Users suddenly missing write permissions to the root drive c within an active directory domain

  - by Kevin

  I'm managing an active directory single domain environment on some Windows Server 2008, Windows Server 2008 R2 and Windows Server 2012 machines. Since a few weeks I got a strange issue. Some users (not all!) report that they cannot any longer save, copy or write files to the root drive c, whether on their clients (vista, win 7) nor via remote desktop connection on a Windows Server 2008 machine. Even running programs that require direct write permissions to the root drive without administrator permissions fail to do so since then. The affected users have local administrator permissions. The question I'm facing now is: What caused this change of system behavior? Why did this happen? I didn't find out yet. What was the last thing I did before it happened? The last action that was made before it happened was the rollout of a GPO containing network drive mappings for the users depending on their security group membership. All network drives are located on a linux server with samba enabled. We did not change any UAC settings, and they have always been activated. However I can't imagine that rolling out this GPO caused the problem. Has anybody faced an issue like that? Just in case: I know that it is for a specific reason that an user without administrative privileges is prevented from writing to the root drive since windows vista and the implementation of UAC. I don't think that those users should be able to write to drive c, but I try to figure out why this is happening and a few weeks ago this was still working. I also know that a user who is a member of the local administrators group does not execute anything with administrator permissions per default unless he or she executes a program with this permissions. What did I do yet? I checked the permissions of the affected programs, the affected clients/server. Didn't find something special. I checked ALL of our GPOs if there exist any restrictions that could prevent the affected users from writing to the root drive. Did not find any settings. I checked the UAC settings of the affected users and compared those to other users that still can write to the root drive. Everything similar. I googled though the internet and tried to find someone who had a similar problem. Did not find one. Has anybody an idea? Thank you very much. Edit: The GPO that was rolled out does the following (Please excuse if the settings are not named exactly like that, I translated the settings into english): **Windows Settings -- Network Drive Mappings -- Drive N: -- General:** Action: Replace **Properties:** Letter: N Location: \\path-to-drive\drivename Re-Establish connection: deactivated Label as: Name_of_the_Share Use first available Option: deactivated **Windows Settings -- Network Drive Mappings -- Drive N: -- Public: Options:** On error don't process any further elements for this extension: no Run as the logged in user: no remove element if it is not applied anymore: no Only apply once: no **Securitygroup:** Attribute -- Value bool -- AND not -- 0 name -- domain\groupname sid -- sid-of-the-group userContext -- 1 primaryGroup -- 0 localGroup -- 0 **Securitygroup:** Attribute -- Value bool -- OR not -- 0 name -- domain\another-groupname sid -- sid-of-the-group userContext -- 1 primaryGroup -- 0 localGroup -- 0 Edit: The Error-Message of an affected users says the following: Due to an unexpected error you can't copy the file. Error-Code 0x80070522: The client is missing a required permission. The command icacls C: shows the following: NT-AUTORITY\SYSTEM:(OI)(CI)(F) PRE-DEFINED\Administrators:(OI)(CI)(F) computername\username:(OI)(CI)(F) A college just told me that also the primary domain-controller (PDC) changed from Windows Server 2008 to Windows Server 2012. That also may be a reason. Any suggestions?

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• What Apache/PHP configurations do you know and how good are they?

  - by FractalizeR

  Hello. I wanted to ask you about PHP/Apache configuration methods you know, their pros and cons. I will start myself: ---------------- PHP as Apache module---------------- Pros: good speed since you don't need to start exe every time especially in mpm-worker mode. You can also use various PHP accelerators in this mode like APC or eAccelerator. Cons: if you are running apache in mpm-worker mode, you may face stability issues because every glitch in any php script will lead to unstability to the whole thread pool of that apache process. Also in this mode all scripts are executed on behalf of apache user. This is bad for security. mpm-worker configuration requires PHP compiled in thread-safe mode. At least CentOS and RedHat default repositories doesn't have thread-safe PHP version so on these OSes you need to compile at least PHP yourself (there is a way to activate worker mpm on Apache). The use of thread-safe PHP binaries is considered experimental and unstable. Plus, many PHP extensions does not support thread-safe mode or were not well-tested in thread-safe mode. ---------------- PHP as CGI ---------------- This seems to be the slowest default configuration which seems to be a "con" itself ;) ---------------- PHP as CGI via mod_suphp ---------------- Pros: suphp allows you to execute php scipts on behalf of the script file owner. This way you can securely separate different sites on the same machine. Also, suphp allows to use different php.ini files per virtual host. Cons: PHP in CGI mode means less performance. In this mode you can't use php accelerators like APC because each time new process is spawned to handle script rendering the cache of previous process useless. BTW, do you know the way to apply some accelerator in this config? I heard something about using shm for php bytecode cache. Also, you cannot configure PHP via .htaccess files in this mode. You will need to install PECL htscanner for this if you need to set various per-script options via .htaccess (php_value / php_flag directives) ---------------- PHP as CGI via suexec ---------------- This configuration looks the same as with suphp, but I heard, that it's slower and less safe. Almost same pros and cons apply. ---------------- PHP as FastCGI ---------------- Pros: FastCGI standard allows single php process to handle several scripts before php process is killed. This way you gain performance since no need to spin up new php process for each script. You can also use PHP accelerators in this configuration (see cons section for comment). Also, FCGI almost like suphp also allows php processes to be executed on behalf of some user. mod_fcgid seems to have the most complete fcgi support and flexibility for apache. Cons: The use of php accelerator in fastcgi mode will lead to high memory consumption because each PHP process will have his own bytecode cache (unless there is some accelerator that can use shared memory for bytecode cache. Is there such?). FastCGI is also a little bit complex to configure. You need to create various configuration files and make some configuration modifications. It seems, that fastcgi is the most stable, secure, fast and flexible PHP configuration, however, a bit difficult to be configured. But, may be, I missed something? Comments are welcome!

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• Unable to make the session state request to the session state server

  - by Angry_IT_Guru

  For about 4-5 months now, I seem to be having this sporadic issue--mainly during our busiest time of the day between 10:30-11:45AM, where all my Windows 2003 web servers in a Microsoft NLB cluster start throwing session state server errors. A sample error is below. System.Web.HttpException: Unable to make the session state request to the session state server. Please ensure that the ASP.NET State service is started and that the client and server ports are the same. If the server is on a remote machine, please ensure that it accepts remote requests by checking the value of HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\aspnet_state\Parameters\AllowRemoteConnection. If the server is on the local machine, and if the before mentioned registry value does not exist or is set to 0, then the state server connection string must use either 'localhost' or '127.0.0.1' as the server name. at System.Web.SessionState.OutOfProcSessionStateStore.MakeRequest(StateProtocolVerb verb, String id, StateProtocolExclusive exclusiveAccess, Int32 extraFlags, Int32 timeout, Int32 lockCookie, Byte[] buf, Int32 cb, Int32 networkTimeout, SessionNDMakeRequestResults& results) at System.Web.SessionState.OutOfProcSessionStateStore.SetAndReleaseItemExclusive(HttpContext context, String id, SessionStateStoreData item, Object lockId, Boolean newItem) at System.Web.SessionState.SessionStateModule.OnReleaseState(Object source, EventArgs eventArgs) at System.Web.HttpApplication.SyncEventExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() at System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) Now I'm using ASP.NET State service on a centralized back-end Windows 2003 server that all servers communicate to. I was originally using SQL Server state for a couple years as well prior to having this issue. The problem with SQL wqas that when the issue occurred, it created a blocking situation which essentially impacted all users across all servers. The product company recommended that I use the standard ASP.NET State service as that was what they technically supported. Why this would make a difference is beyond me -- but I had no choice but to try it! I have attempted to create multiple application pools, adding additional servers, chaning TCP/IP timeout from 20 to 30 seconds, and even calling Microsoft ASP.NET product support, with very little success. I even recommended that they review whether they are using read-only session state instead of read/write per page request -- as I understand that this basically causes every page to make round-trips to state server even if state isn't being used on the page. Unfortunately, the application is developed by our product company and they insist that it is something with my environment because other clients do not have these sort of issues. However, I've talked to other clients and they tell me when they've seen issues like they, they've basically had to create another web farm. This issue almost seems like I've simply reached some architectural limit within the application... Microsoft's position on the issue is that the session state needs to be reduced and the returncode being reported back from the state server indicates buffers are full. To better understand the scope of issues (rather than wait for customers to call and complain), I installed ELMAH and configured it to send me e-mails when unhandled exceptions occur. I basically get 500-1000 e-mails during the time period of high activity! If any one has any other ideas I could try or better ways to troubleshoot, I'd appreciate it.

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• Why wireless adatper stop to work?

  - by AndreaNobili

  today I correctly installed the driver for the TP-LINK TL-WN725N USB wireless adapter on my RaspBerry Pi (I use RaspBian that is a Debian), then I setted up the wifi using the wpa-supplicant as explained in this tutorial: http://www.maketecheasier.com/setup-wifi-on-raspberry-pi/ This worked fine untill this evening. Then suddenly it stopped to work when I try to connect in SSH and the Raspberry is on the wireless (or rather it should be, as this is not in the list of my router's DHCP connected Client) The strange thing is that the USB wirless adapter blink so I think that this is not a driver problem. If I try to connect it by the ethernet I have no problem. It appear in my router's DHCP connected Client and I can connect to it by SSH. When I connect to it using ethernet if I perform an ifconfig command I obtain: pi@raspberrypi ~ $ ifconfig eth0 Link encap:Ethernet HWaddr b8:27:eb:2a:9f:b0 inet addr:192.168.1.9 Bcast:192.168.1.255 Mask:255.255.255.0 UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:48 errors:0 dropped:0 overruns:0 frame:0 TX packets:59 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:6006 (5.8 KiB) TX bytes:8268 (8.0 KiB) lo Link encap:Local Loopback inet addr:127.0.0.1 Mask:255.0.0.0 UP LOOPBACK RUNNING MTU:65536 Metric:1 RX packets:8 errors:0 dropped:0 overruns:0 frame:0 TX packets:8 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:1104 (1.0 KiB) TX bytes:1104 (1.0 KiB) wlan0 Link encap:Ethernet HWaddr e8:94:f6:19:80:4c UP BROADCAST MULTICAST MTU:1500 Metric:1 RX packets:0 errors:0 dropped:0 overruns:0 frame:0 TX packets:0 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:0 (0.0 B) TX bytes:0 (0.0 B) So it seems that the wlan0 USB wireless adapter driver is correctly loaded. If I remove the USB wireless adapter and put it again into the USB port, the lasts lines of dmesg log is: [ 20.303172] smsc95xx 1-1.1:1.0 eth0: hardware isn't capable of remote wakeup [ 20.306340] RTL871X: set bssid:00:00:00:00:00:00 [ 20.306726] RTL871X: set ssid [g\xffffffc6isQ\xffffffffJ\xffffffec)\xffffffcd\xffffffba\xffffffba\xffffffab\xfffffff2\xfffffffb\xffffffe3F|\xffffffc2T\xfffffff8\x1b\xffffffe8\xffffffe7\xffffff8dvZ.c3\xffffff9f\xffffffc9\xffffff9a\xffffff9aD\xffffffa7\x1a\xffffffa0\x1a\xffffff8b] fw_state=0x00000008 [ 21.614585] RTL871X: indicate disassoc [ 21.908495] smsc95xx 1-1.1:1.0 eth0: link up, 100Mbps, full-duplex, lpa 0x45E1 [ 25.006282] Adding 102396k swap on /var/swap. Priority:-1 extents:1 across:102396k SSFS [ 26.247997] RTL871X: nolinked power save enter As you can see some of these line are related to the RTL871X that is my USB wireless adapter, but I don't know is that these line report an error or if it is all ok. Looking at the adapter status I obtain: pi@raspberrypi ~ $ ip link list dev wlan0 3: wlan0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc mq state DOWN mode DORMANT qlen 1000 link/ether e8:94:f6:19:80:4c brd ff:ff:ff:ff:ff:ff As you can see the mode is DORMANT but I think that this is normal because now I am connected using ethernet. I tryied to set up the adapter but it seems that I obtain no result, infact: pi@raspberrypi ~ $ sudo ip link set dev wlan0 up pi@raspberrypi ~ $ ip link list dev wlan0 3: wlan0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc mq state DOWN mode DORMANT qlen 1000 link/ether e8:94:f6:19:80:4c brd ff:ff:ff:ff:ff:ff pi@raspberrypi ~ $ sudo ip link set dev wlan0 up This is my /etc/network/interfaces file content and it is ok: auto lo iface lo inet loopback iface eth0 inet dhcp allow-hotplug wlan0 iface wlan0 inet manual wpa-roam /etc/wpa_supplicant/wpa_supplicant.conf iface default inet dhcp and it is the /etc/wpa_supplicant/wpa_supplicant.conf that I think is ok (I did not change it compared to when it worked): ctrl_interface=DIR=/var/run/wpa_supplicant GROUP=netdev update_config=1 network={ ssid="MY-NETWORK" psk="mypassword" key_mgmt=WPA-PSK } and infact if I execute a network scan I correctly find MY-NETWORK in the network list,infact: pi@raspberrypi ~ $ sudo iwlist wlan0 scan | grep ESSID ESSID:"TeleTu_74888B0060AD" ESSID:"MY-NETWORK" ESSID:"FASTWEB-1-PT6NtjL4TOSe" ESSID:"DC" So I reboot the system and I remove the ethernet cable but when I try to connect again to my raspberry I obatin the following error message: andrea@andrea-virtual-machine:~$ sudo ssh [email protected] ssh: connect to host 192.168.1.9 port 22: No route to host It seems that it can't connect using wireless. What could be the problem? What am I missing? How can I solve this situation? Tnx

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• Deploying play! 2.0 application on an apache server with a reverse proxy

  - by locrizak

  I'm trying to deploy my play! 2.0 application on an Ubuntu 11.10 server and I have been running into error after error and hope someone can help me here. I am try to deploy my Play! application using a reverse proxy on Apache 2. I have enabled the apache proxy modules and configured the proxy.conf file in mods_enabled. The vhost for my domain looks like this: <Directory /var/www/stage.domain.com AllowOverride None Order Deny,Allow Deny from all </Directory <VirtualHost *:80 DocumentRoot /var/www/stage.domain.com/web ServerName stage.domain.com ServerAdmin [email protected] # ProxyRequests Off # ProxyPreserveHost On <Proxy * Order allow,deny Allow from all </Proxy # ProxyVia On # ProxyPass /play/ http://localhost:9000/ # ProxyPassReverse /play/ http://localhost:9000/ ErrorLog /var/log/ispconfig/httpd/stage.domain.com/error.log ErrorDocument 400 /error/400.html ErrorDocument 401 /error/401.html ErrorDocument 403 /error/403.html ErrorDocument 404 /error/404.html ErrorDocument 405 /error/405.html ErrorDocument 500 /error/500.html ErrorDocument 502 /error/502.html ErrorDocument 503 /error/503.html <IfModule mod_ssl.c </IfModule <Directory /var/www/stage.domain.com/web Options FollowSymLinks AllowOverride All Order allow,deny Allow from all </Directory <Directory /var/www/clients/client2/web7/web Options FollowSymLinks AllowOverride All Order allow,deny Allow from all </Directory # Clear PHP settings of this website <FilesMatch "\.ph(p3?|tml)$" SetHandler None </FilesMatch # mod_php enabled AddType application/x-httpd-php .php .php3 .php4 .php5 php_admin_value sendmail_path "/usr/sbin/sendmail -t -i [email protected]" php_admin_value upload_tmp_dir /var/www/clients/client2/web7/tmp php_admin_value session.save_path /var/www/clients/client2/web7/tmp # PHPIniDir /var/www/conf/web7 php_admin_value open_basedir /var/www/clients/client2/web7/:/var/www/clients/client2/web7/web:/va$ # add support for apache mpm_itk <IfModule mpm_itk_module AssignUserId web7 client2 </IfModule <IfModule mod_dav_fs.c # Do not execute PHP files in webdav directory <Directory /var/www/clients/client2/web7/webdav <FilesMatch "\.ph(p3?|tml)$" SetHandler None </FilesMatch </Directory # DO NOT REMOVE THE COMMENTS! # IF YOU REMOVE THEM, WEBDAV WILL NOT WORK ANYMORE! # WEBDAV BEGIN # WEBDAV END </IfModule # <Location /play/ # ProxyPass http://localhost:9000/ # SetEnv force-proxy-request-1.0 1 # SetEnv proxy-nokeepalive 1 # </Location ProxyRequests Off ProxyPass /play/ http://localhost:9000/ ProxyPassReverse /play/ localhost:9000/ ProxyPass /play http://localhost:9000/ ProxyPassReverse /play http://localhost:9000/ # SetEnv force-proxy-request-1.0 1 # SetEnv proxy-nokeepalive 1 </VirtualHost This vhost file was generated by ispconfig and I have not touched anything that was there before just added onto. As you can see by the commented out parts I have tried a lot of different things based on random tutorials I have found but all of them have ended up in Internal Server Error, 503 and most often a '502 Bad Gateway`. I can start play and it does connect successfully to my database. I can get a page to show up when there is an error and the play! stack trace error pages comes up but where everything is fine I get one of the errors above. My application.conf file looks like this: db info ....... application.mode=PROD logger.root=ERROR # Logger used by the framework: logger.play=INFO # Logger provided to your application: logger.application=DEBUG http.path="/play/" XForwardedSupport="127.0.0.1" And my hosts file looks like this (I have never changed or added anything to the host file): 127.0.0.1 localhost 127.0.1.1 matrix # The following lines are desirable for IPv6 capable hosts ::1 ip6-localhost ip6-loopback fe00::0 ip6-localnet ff00::0 ip6-mcastprefix ff02::1 ip6-allnodes ff02::2 ip6-allrouters Any insights onto what I might be doing wrong or if theres anything I can try please let me know! Thanks!! Edit Again the reverse proxy will work (I checked with sending to to google.com). Its when there is a successful connection to Netty. It's like Netty refuses the connection to the page. Edit 2 output from apachectl -S _default_:8081 127.0.0.1 (/etc/apache2/sites-enabled/000-apps.vhost:10) *:8090 is a NameVirtualHost default server 127.0.0.1 (/etc/apache2/sites-enabled/000-ispconfig.vhost:10) port 8090 namevhost 127.0.0.1 (/etc/apache2/sites-enabled/000-ispconfig.vhost:10) *:80 is a NameVirtualHost default server 127.0.0.1 (/etc/apache2/sites-enabled/000-default:1) port 80 namevhost 127.0.0.1 (/etc/apache2/sites-enabled/000-default:1) port 80 namevhost domain.com (/etc/apache2/sites-enabled/100-domain.com.vhost:7) port 80 namevhost domain.com (/etc/apache2/sites-enabled/100-domain.com.vhost:7) port 80 namevhost domain.com (/etc/apache2/sites-enabled/100-domain.com.vhost:7) port 80 namevhost domain.com (/etc/apache2/sites-enabled/100-domain.com.vhost:7) port 80 namevhost domain.com (/etc/apache2/sites-enabled/100-domain.com.vhost:7) port 80 namevhost stage.domain.com (/etc/apache2/sites-enabled/100-stage.domain.com.vhost:7) port 80 namevhost domain.com (/etc/apache2/sites-enabled/100-domain.com.vhost:7)

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• Automatically starting svnserve on Snow Leopard

  - by Cleggy

  Note: I originally asked this question on Server Fault (http://serverfault.com/questions/148052/automatically-starting-svnserve-on-snow-leopard), but I thought this may be a more appropriate place to ask. I have installed Subversion onto my iMac running Snow Leopard, but am having trouble getting svnserve to start up automatically. As I understand it (I'm still fairly green with OSX), the best way to do that is to utilize launchd. To that end, I have created the following .plist file in the /Library/LaunchDaemons folder. If I use launchctl to execute this file, svnserve starts as expected, but it doesn't automatically start when the system starts up or I log in. <?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd"> <plist version="1.0"> <dict> <key>Disabled</key> <false/> <key>Label</key> <string>org.tigris.subversion.svnserve</string> <key>UserName</key> <string>Dave</string> <key>ProgramArguments</key> <array> <string>/opt/subversion/bin/svnserve</string> <string>--inetd</string> <string>--root=/Users/Shared/SVNrep</string> </array> <key>ServiceDescription</key> <string>Subversion Standalone Server</string> <key>Sockets</key> <dict> <key>Listeners</key> <array> <dict> <key>SockFamily</key> <string>IPv4</string> <key>SockServiceName</key> <string>svn</string> <key>SockType</key> <string>stream</string> </dict> <dict> <key>SockFamily</key> <string>IPv6</string> <key>SockServiceName</key> <string>svn</string> <key>SockType</key> <string>stream</string> </dict> </array> </dict> <key>inetdCompatibility</key> <dict> <key>Wait</key> <false/> </dict> </dict> </plist> I have tried many different configs in the .plist, including auto-starting, simplifying the listeners section, removing dependence on inetd, but they all show the same symptom. The files work when started using launchctl load, but do not automatically start up svnserve if the iMac is rebooted. If anyone here could provide any suggestions as to how to get this to work, I'd really appreciate it.

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• IIS 7.5 Manager crashes when adding a custom error page

  - by dig412

  I'm running a local IIS 7.5 server in Win 7 Pro, and I'm trying to add a custom error page for 403 responses. When I click OK to add a custom error page for my site, IIS Manager just vanishes. The server is still running, and I can re-start IIS Manager, but the new page has not been saved. I've also tried adding it directly to web.config, but that just gives me The page cannot be displayed because an internal server error has occurred. Does anyone know why this might be happening? Edit: The event log implies that an invalid character in the path caused the crash, but It occured even when I copied & pasted a path from a valid entry. Application error log: IISMANAGER_CRASH IIS Manager terminated unexpectedly. Exception:System.Reflection.TargetInvocationException: Exception has been thrown by the target of an invocation. --- System.ArgumentException: Illegal characters in path. at System.IO.Path.CheckInvalidPathChars(String path) at System.IO.Path.IsPathRooted(String path) at Microsoft.Web.Management.Iis.CustomErrors.CustomErrorsForm.OnAccept() at Microsoft.Web.Management.Client.Win32.TaskForm.OnOKButtonClick(Object sender, EventArgs e) at System.Windows.Forms.Control.OnClick(EventArgs e) at System.Windows.Forms.Button.OnMouseUp(MouseEventArgs mevent) at System.Windows.Forms.Control.WmMouseUp(Message& m, MouseButtons button, Int32 clicks) at System.Windows.Forms.Control.WndProc(Message& m) at System.Windows.Forms.ButtonBase.WndProc(Message& m) at System.Windows.Forms.Button.WndProc(Message& m) at System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m) at System.Windows.Forms.NativeWindow.DebuggableCallback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam) at System.Windows.Forms.UnsafeNativeMethods.DispatchMessageW(MSG& msg) at System.Windows.Forms.Application.ComponentManager.System.Windows.Forms.UnsafeNativeMethods.IMsoComponentManager.FPushMessageLoop(Int32 dwComponentID, Int32 reason, Int32 pvLoopData) at System.Windows.Forms.Application.ThreadContext.RunMessageLoopInner(Int32 reason, ApplicationContext context) at System.Windows.Forms.Application.ThreadContext.RunMessageLoop(Int32 reason, ApplicationContext context) at System.Windows.Forms.Form.ShowDialog(IWin32Window owner) at Microsoft.Web.Management.Host.UserInterface.ManagementUIService.ShowDialogInternal(Form form, IWin32Window parent) at Microsoft.Web.Management.Host.UserInterface.ManagementUIService.Microsoft.Web.Management.Client.Win32.IManagementUIService.ShowDialog(DialogForm form) at Microsoft.Web.Management.Client.Win32.ModulePage.ShowDialog(DialogForm form) at Microsoft.Web.Management.Iis.CustomErrors.CustomErrorsPage.AddCustomError() --- End of inner exception stack trace --- at System.RuntimeMethodHandle._InvokeMethodFast(Object target, Object[] arguments, SignatureStruct& sig, MethodAttributes methodAttributes, RuntimeTypeHandle typeOwner) at System.Reflection.RuntimeMethodInfo.Invoke(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture, Boolean skipVisibilityChecks) at System.Reflection.RuntimeMethodInfo.Invoke(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture) at Microsoft.Web.Management.Client.TaskList.InvokeMethod(String methodName, Object userData) at Microsoft.Web.Management.Host.UserInterface.Tasks.MethodTaskItemLine.InvokeMethod() at System.Windows.Forms.LinkLabel.OnMouseUp(MouseEventArgs e) at System.Windows.Forms.Control.WmMouseUp(Message& m, MouseButtons button, Int32 clicks) at System.Windows.Forms.Control.WndProc(Message& m) at System.Windows.Forms.Label.WndProc(Message& m) at System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m) at System.Windows.Forms.NativeWindow.DebuggableCallback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam) at System.Windows.Forms.UnsafeNativeMethods.DispatchMessageW(MSG& msg) at System.Windows.Forms.Application.ComponentManager.System.Windows.Forms.UnsafeNativeMethods.IMsoComponentManager.FPushMessageLoop(Int32 dwComponentID, Int32 reason, Int32 pvLoopData) at System.Windows.Forms.Application.ThreadContext.RunMessageLoopInner(Int32 reason, ApplicationContext context) at System.Windows.Forms.Application.ThreadContext.RunMessageLoop(Int32 reason, ApplicationContext context) at Microsoft.Web.Management.Host.Shell.ShellApplication.Execute(Boolean localDevelopmentMode, Boolean resetPreferences, Boolean resetPreferencesNoLaunch) Process:InetMgr

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• FreeBSD with Vagrant - don't know how to check guest additions version

  - by joelmaranhao

  On Mac OS X 10.9.3 Picked a box from the VagrantCloud Init the vagrant box $ vagrant init chef/freebsd-9.2-i386 A `Vagrantfile` has been placed in this directory. You are now ready to `vagrant up` your first virtual environment! Please read the comments in the Vagrantfile as well as documentation on `vagrantup.com` for more information on using Vagrant. List the files $ ls -al -rw-r--r-- 1 joel staff 4831 Jun 5 17:17 Vagrantfile Vagrantfile content VAGRANTFILE_API_VERSION = "2" Vagrant.configure(VAGRANTFILE_API_VERSION) do |config| config.vm.box = "chef/freebsd-9.2-i386" end Starting my virtual box leads to Errors $ vagrant up Bringing machine 'default' up with 'virtualbox' provider... ==> default: Box 'chef/freebsd-9.2-i386' could not be found. Attempting to find and install... default: Box Provider: virtualbox default: Box Version: >= 0 ==> default: Loading metadata for box 'chef/freebsd-9.2-i386' default: URL: https://vagrantcloud.com/chef/freebsd-9.2-i386 ==> default: Adding box 'chef/freebsd-9.2-i386' (v1.0.0) for provider: virtualbox default: Downloading: https://vagrantcloud.com/chef/freebsd-9.2-i386/version/1/provider/virtualbox.box ==> default: Successfully added box 'chef/freebsd-9.2-i386' (v1.0.0) for 'virtualbox'! ==> default: Importing base box 'chef/freebsd-9.2-i386'... ==> default: Matching MAC address for NAT networking... ==> default: Checking if box 'chef/freebsd-9.2-i386' is up to date... ==> default: Setting the name of the VM: freebsd92-i386_default_1401982167145_49633 ==> default: Fixed port collision for 22 => 2222. Now on port 2201. ==> default: Clearing any previously set network interfaces... ==> default: Preparing network interfaces based on configuration... default: Adapter 1: nat ==> default: Forwarding ports... default: 22 => 2201 (adapter 1) ==> default: Booting VM... ==> default: Waiting for machine to boot. This may take a few minutes... default: SSH address: 127.0.0.1:2201 default: SSH username: vagrant default: SSH auth method: private key default: Warning: Connection timeout. Retrying... default: Warning: Connection timeout. Retrying... ==> default: Machine booted and ready! Sorry, don't know how to check guest version of Virtualbox Guest Additions on this platform. Stopping installation. ==> default: Checking for guest additions in VM... default: The guest additions on this VM do not match the installed version of default: VirtualBox! In most cases this is fine, but in rare cases it can default: prevent things such as shared folders from working properly. If you see default: shared folder errors, please make sure the guest additions within the default: virtual machine match the version of VirtualBox you have installed on default: your host and reload your VM. default: default: Guest Additions Version: 4.2.16 default: VirtualBox Version: 4.3 ==> default: Mounting shared folders... default: /vagrant => /Users/joel/Code/anybots/operations/robot/freebsd92-i386 Vagrant attempted to execute the capability 'mount_virtualbox_shared_folder' on the detect guest OS 'freebsd', but the guest doesn't support that capability. This capability is required for your configuration of Vagrant. Please either reconfigure Vagrant to avoid this capability or fix the issue by creating the capability. Note that I have recently installed the latest version of VirtualBox, but somehow I can't find the Guest Additions.

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• Call to daemon in a /etc/init.d script is blocking, not running in background

  - by tony

  I have a Perl script that I want to daemonize. Basically this perl script will read a directory every 30 seconds, read the files that it finds and then process the data. To keep it simple here consider the following Perl script (called synpipe_server, there is a symbolic link of this script in /usr/sbin/) : #!/usr/bin/perl use strict; use warnings; my $continue = 1; $SIG{'TERM'} = sub { $continue = 0; print "Caught TERM signal\n"; }; $SIG{'INT'} = sub { $continue = 0; print "Caught INT signal\n"; }; my $i = 0; while ($continue) { #do stuff print "Hello, I am running " . ++$i . "\n"; sleep 3; } So this script basically prints something every 3 seconds. Then, as I want to daemonize this script, I've also put this bash script (also called synpipe_server) in /etc/init.d/ : #!/bin/bash # synpipe_server : This starts and stops synpipe_server # # chkconfig: 12345 12 88 # description: Monitors all production pipelines # processname: synpipe_server # pidfile: /var/run/synpipe_server.pid # Source function library. . /etc/rc.d/init.d/functions pname="synpipe_server" exe="/usr/sbin/synpipe_server" pidfile="/var/run/${pname}.pid" lockfile="/var/lock/subsys/${pname}" [ -x $exe ] || exit 0 RETVAL=0 start() { echo -n "Starting $pname : " daemon ${exe} RETVAL=$? PID=$! echo [ $RETVAL -eq 0 ] && touch ${lockfile} echo $PID > ${pidfile} } stop() { echo -n "Shutting down $pname : " killproc ${exe} RETVAL=$? echo if [ $RETVAL -eq 0 ]; then rm -f ${lockfile} rm -f ${pidfile} fi } restart() { echo -n "Restarting $pname : " stop sleep 2 start } case "$1" in start) start ;; stop) stop ;; status) status ${pname} ;; restart) restart ;; *) echo "Usage: $0 {start|stop|status|restart}" ;; esac exit 0 So, (if I have well understood the doc for daemon) the Perl script should run in the background and the output should be redirected to /dev/null if I execute : service synpipe_server start But here is what I get instead : [root@master init.d]# service synpipe_server start Starting synpipe_server : Hello, I am running 1 Hello, I am running 2 Hello, I am running 3 Hello, I am running 4 Caught INT signal [ OK ] [root@master init.d]# So it starts the Perl script but runs it without detaching it from the current terminal session, and I can see the output printed in my console ... which is not really what I was expecting. Moreover, the PID file is empty (or with a line feed only, no pid returned by daemon). Does anyone have any idea of what I am doing wrong ? EDIT : maybe I should say that I am on a Red Hat machine. Scientific Linux SL release 5.4 (Boron) Would it do the job if instead of using the daemon function, I use something like : nohup ${exe} >/dev/null 2>&1 & in the init script ?

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• Why am I getting a 403 error on a POST to a PHP script?

  - by John Gallagher

  Background I want to allow my users to submit a crash report which will get emailed to me. I'm using UKCrashReporter with the bundled PHP script I've modified. This code does a POST to a specified URL along with the crash report. I'm on a shared server running Linux. My main domain is synapticmishap.co.uk. The Problem When I send the crash report off, on the Cocoa side, it reports as having sent it successfully, but I don't receive an email. The code has been used in lots of other well established Cocoa projects and it was working for me a few months ago. That leads me to conclude that the problems are related to my web server setup, something I know almost nothing about. When I look at my log files, I see entries like this: IP Redacted - - [10/Jun/2010:09:47:53 +0100] "POST /synapticmishap/crashreportform.php HTTP/1.1" 403 74 "-" "UKCrashReporter" What I've tried I've tried accessing the page at http://synapticmishap.co.uk/synapticmishap/crashreportform.php via a browser. It loads fine. I've made sure the permissions on this php script are set so anyone can execute it. I've tried removing the deny entries from the section of .htaccess at various levels starting with root. I've downloaded the URLParams plugin for Firefox which allows you to simulate POSTs. I put in the URL above and tried a post with "crashlog" as the parameter and "test" as the value. This generated a 200 log entry in my log file - it seemed to work, although no mail message was sent. Code I've got the following at http://synapticmishap.co.uk/synapticmishap/crashreportform.php. I've simplified it to just the bare bones in an effort to get it working. <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd"> <html> <head> <title>Crash Report</title> </head> <body> <p>This page contains super special magic which submits a crash report item to me.</p> <p>Nothing to see here - move along.</p> <?php mail( "[email protected]", "Crash Report", "\r\n\r\nThis is a test."); ?> </body> </html> This is my top level .htaccess file: RewriteEngine on # -FrontPage- IndexIgnore .htaccess */.??* *~ *# */HEADER* */README* */_vti* <Limit GET POST> order deny,allow deny from all allow from all </Limit> <Limit PUT DELETE> order deny,allow deny from all </Limit> Options All -Indexes RewriteCond %{HTTP_HOST} ^synapticmishap.co.uk$ [OR] RewriteCond %{HTTP_HOST} ^www.synapticmishap.co.uk$ RewriteCond %{HTTP_HOST} ^lapsusapp.co.uk$ [OR] RewriteCond %{HTTP_HOST} ^www.lapsusapp.co.uk$ RewriteRule ^/?$ "http\:\/\/synapticmishap\.co\.uk\/synapticmishap\/lapsuspromo\/" [R=301,L] RewriteCond %{HTTP_HOST} ^jgtutoring.co.uk$ [OR] RewriteCond %{HTTP_HOST} ^www.jgtutoring.co.uk$ RewriteRule ^/?$ "http\:\/\/synapticmishap\.co\.uk\/tutoring" [R=301,L] RewriteCond %{HTTP_HOST} ^synapticmishap.co.uk$ [OR] RewriteCond %{HTTP_HOST} ^www.synapticmishap.co.uk$ RewriteRule ^/?$ "http\:\/\/synapticmishap\.co\.uk\/synapticmishap" [R=301,L] RewriteCond %{HTTP_HOST} ^jgediting.co.uk$ [OR] RewriteCond %{HTTP_HOST} ^www.jgediting.co.uk$ RewriteRule ^/?$ "http\:\/\/synapticmishap\.co\.uk\/editing" [R=301,L] RewriteCond %{HTTP_REFERER} !^$ RewriteCond %{HTTP_REFERER} !^http://synapticmishap.co.uk/.*$ [NC] RewriteCond %{HTTP_REFERER} !^http://synapticmishap.co.uk$ [NC] RewriteCond %{HTTP_REFERER} !^http://www.synapticmishap.co.uk/.*$ [NC] RewriteCond %{HTTP_REFERER} !^http://www.synapticmishap.co.uk$ [NC] RewriteCond %{HTTP_REFERER} !^http://synapticmishap.co.uk/synapticmishap/crashreportform.php/.*$ [NC] RewriteCond %{HTTP_REFERER} !^http://synapticmishap.co.uk/synapticmishap/crashreportform.php$ [NC] RewriteRule .*\.(jpg|jpeg|gif|png|bmp)$ - [F,NC] Help! I'm at the end of my tether with this and I'm in a very unfamiliar space with all this web stuff. I'd be most appreciative of any thoughts people had on why this isn't working. Thanks.

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• Do email forms need to be santized before sending?

  - by levi

  I have a client that keeps getting reports from godaddy's "websiteprotection.com" stating how the website is insecure. Your website contains pages that do not properly sanitize visitor-provided input to make sure it contains no malicious content or scripts. Cross-site scripting vulnerabilities let malicious users execute arbitrary HTML or script code in another visitor's browser. Output: The request string used to detect this flaw was : /cross_site_scripting.?nasl.asp The output was : HTTP/1.1 404 Not Found\r Date: Wed, 21 Mar 2012 08:12:02 GMT\r Server: Apache\r X-Pingback:http://?CLIENTSWEBSITE.com/?xmlrpc.php\r Expires: Wed, 11 Jan 1984 05:00:00 GMT\r Cache-Control: no-cache, must-revalidate, max-age=0\r Pragma: no-cache\r Set-Cookie: PHPSESSID=?1jsnhuflvd59nb4trtquston50; path=/\r Last-Modified: Wed, 21 Mar 2012 08:12:02 GMT\r Keep-Alive: timeout=15, max=100\r Connection: Keep-Alive\r Transfer-Encoding: chunked\r Content-Type: text/html; charset=UTF-8\r \r <div id="contact-form" class="widget"><form action="http://?CLIENTSWEBSITE.c om/<script>cross_site_?scripting.nasl</script>.asp" id="contactForm" meth od="post"> It looks like it has an issue with the contact form. All the contact form does is posts an ajax request to the same page, and than a PHP script mails the data (no database stuff). Is there any a security issues here? Any ideas on how I can satisfy the security scanner? Here is the form and script: <form action="<?php echo $this->getCurrentUrl(); ?>" id="contactForm" method="post"> <input type="text" name="Name" id="Name" value="" class="txt requiredField name" /> //Some more text inputs <input type="hidden" name="sendadd" id="sendadd" value="<?php echo $emailadd ; ?>" /> <input type="hidden" name="submitted" id="submitted" value="true" /><input class="submit" type="submit" value="Send" /> </form> // Some initial JS validation, if that passes an ajax post is made to the script below //If the form is submitted if(isset($_POST['submitted'])) { //Check captcha if (isset($_POST["captchaPrefix"])) { $capt = new ReallySimpleCaptcha(); $correct = $capt->check( $_POST["captchaPrefix"], $_POST["Captcha"] ); if( ! $correct ) { echo false; die(); } else { $capt->remove( $_POST["captchaPrefix"] ); } } $dateon = $_POST["dateon"]; $ToEmail = $_POST["sendadd"]; $EmailSubject = 'Contact Form Submission from ' . get_bloginfo('title'); $mailheader = "From: ".$_POST["Email"]."\r\n"; $mailheader .= "Reply-To: ".$_POST["Email"]."\r\n"; $mailheader .= "Content-type: text/html; charset=iso-8859-1\r\n"; $MESSAGE_BODY = "Name: ".$_POST["Name"]."<br>"; $MESSAGE_BODY .= "Email Address: ".$_POST["Email"]."<br>"; $MESSAGE_BODY .= "Phone: ".$_POST["Phone"]."<br>"; if ($dateon == "on") {$MESSAGE_BODY .= "Date: ".$_POST["Date"]."<br>";} $MESSAGE_BODY .= "Message: ".$_POST["Comments"]."<br>"; mail($ToEmail, $EmailSubject, $MESSAGE_BODY, $mailheader) or die ("Failure"); echo true; die(); }

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• Automatically starting svnserve on Snow Leopard

  - by Cleggy

  I have installed Subversion onto my iMac running Snow Leopard, but am having trouble getting svnserve to start up automatically. As I understand it (I'm still fairly green with OSX), the best way to do that is to utilize launchd. To that end, I have created the following .plist file in the /Library/LaunchDaemons folder. If I use launchctl to execute this file, svnserve starts as expected, but it doesn't automatically start when the system starts up or I log in. <?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd"> <plist version="1.0"> <dict> <key>Disabled</key> <false/> <key>Label</key> <string>org.tigris.subversion.svnserve</string> <key>UserName</key> <string>Dave</string> <key>ProgramArguments</key> <array> <string>/opt/subversion/bin/svnserve</string> <string>--inetd</string> <string>--root=/Users/Shared/SVNrep</string> </array> <key>ServiceDescription</key> <string>Subversion Standalone Server</string> <key>Sockets</key> <dict> <key>Listeners</key> <array> <dict> <key>SockFamily</key> <string>IPv4</string> <key>SockServiceName</key> <string>svn</string> <key>SockType</key> <string>stream</string> </dict> <dict> <key>SockFamily</key> <string>IPv6</string> <key>SockServiceName</key> <string>svn</string> <key>SockType</key> <string>stream</string> </dict> </array> </dict> <key>inetdCompatibility</key> <dict> <key>Wait</key> <false/> </dict> </dict> </plist> If anyone here could provide any suggestions as to how to get this to work, I'd really appreciate it.

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• apache webserver unresponsible with server-status showing all child processes waiting for connection

  - by Jeff

  My setup: i have 3 nearly identical webserver machines serving the same high loaded dynamic website with simple load balancing over dns. The service has been working for over two ears with the same apache config. apache2, php5, ubuntu 8.04 linux 2.6.24-29-server My problem: since about two weeks i'm experiencing problems with this config. Nearly every day i have one small moment about 5 minutes, in which the website is unreachable. I'm still able to login to the servers over ssh. If i run htop, i see the machine simply doing nothing. i have about 1000 apache processes running, but no cpu activity. i've used the apache mod_status to debug this situation. the process scoreboard looks like this: _C.___K_______________________R._______.__K_K____K___C_______.__ _______C__________.___________________________________.________C _.____K__________K___K_WK_____._K_____________________________._ W______K__________K________.____________________._______C_______ _C_.__K__K____.._.._____________________________________C_______ _R___________K___.______C________.C_________.______._____C______ ____________KKC____K_____K__WC_________________C_____.__.____.__ _____________________C_________K______.____C______._____________ _.___C____.___.___________________________.K______.____K________ W__.___________________C.__.____K________K_______R_._.__._______ __C__C_.__________C__C_______._____W______________C_.___C_______ ____.______C_____________C________.____C____________.________._K __.__________.K_____________K_________._____C____.K__________KW_ __K.W________R_________._______.___W___________.____.__K_____W__ W___.___..________W____K Scoreboard Key: "_" Waiting for Connection, "S" Starting up, "R" Reading Request, "W" Sending Reply, "K" Keepalive (read), "D" DNS Lookup, "C" Closing connection, "L" Logging, "G" Gracefully finishing, "I" Idle cleanup of worker, "." Open slot with no current process So the most of the processes are just waiting for connection. after about 5 minutes the situation will return to normal: i have lot least processes on every machine, the most workers have the "."-status (meaing they are open to process a request) and of course the website is reachable! so i'm trying to find something in the logs, but there is simply nothing... the apache access log is silent for about 4 minutes, the same is for the error log. i also can not figure out anything wrong in other system logs. the situation is the same on all 3 webservers (all of them have this load peak and unresposibility at the same time), so i do not thing this is hardware related. but i think, this might be related to some network (tcp) issue. any ideas? EDIT: some more information, that i have just discovered: it has just happened again. and i was able to verify that i'm also not able to connect locally when this problem occurs. i have made some connection statistics with the following command after it happend netstat -an|awk '/tcp/ {print $6}'|sort|uniq -c 109 CLOSE_WAIT 2652 ESTABLISHED 2 FIN_WAIT1 11 LAST_ACK 12 LISTEN 91 SYN_RECV 1 SYN_SENT 16 TIME_WAIT If i execute the same command some time later, i have something like this: 4 CLOSING 108 ESTABLISHED 18 FIN_WAIT1 182 FIN_WAIT2 37 LAST_ACK 12 LISTEN 50 SYN_RECV 11276 TIME_WAIT So in the normal situation i have only 100-200 open connections by clients beeing handled by apache in this moment. when i have this "crash", i have a lot more connections. what is the best way to analyse this? EDIT2: the important lines in apache2.conf are: KeepAlive On MaxKeepAliveRequests 20 KeepAliveTimeout 1 <IfModule mpm_prefork_module> ServerLimit 920 StartServers 30 MinSpareServers 80 MaxSpareServers 120 MaxClients 920 MaxRequestsPerChild 700 </IfModule> it is an apache2 prefork with php_mod. the server has 8GB ram and a 4gb swap partition.

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• All my sites are 403 but the server is running. Errors on startup

  - by Craig

  We gave access to a contractor to install a firewall and somehow while he was doing it he fracked something up. Everything went off-line about 24 hours ago and we are effectively out of business until I solve this and the person who messed up the thing is not returning calls. I found a few errors. First, I'm not a server guy - I can look at log files and normally everything runs fine. All 'services' are running according to 1and1 server monitoring and mail is being delivered just fine. The whole thing was off-line until I (probably stupidly) updated the kernel from 6.2 to 6.3 this morning and I got everything back except the http access. All the domains (~200 of them) are returning a 403 error and nothing is recorded in the access log. On every restart I see this error in the messages log file: init: Failed to spawn ttyS0 main process: unable to execute: No such file or directory and a little later these: kernel: WARNING: at kernel/sched.c:5914 thread_return+0x232/0x79d() (Not tainted) kernel: Hardware name: X9SCL/X9SCM kernel: Modules linked in: xt_iprange iptable_filter ip_tables ip6t_REJECT nf_conntrack_ipv6 nf_defrag_ipv6 xt_state nf_conntrack ip6table_filter ip6_tables ipv6 ext4 jbd2 serio_raw i2c_i801 i2c_core sg iTCO_wdt iTCO_vendor_support e1000e ext3 jbd mbcache raid1 sd_mod crc_t10dif ahci dm_mirror dm_region_hash dm_log dm_mod [last unloaded: scsi_wait_scan] kernel: Pid: 367, comm: md3_raid1 Not tainted 2.6.32-220.2.1.el6.x86_64 #1 kernel: Call Trace: kernel: [<ffffffff81069997>] ? warn_slowpath_common+0x87/0xc0 kernel: [<ffffffff810699ea>] ? warn_slowpath_null+0x1a/0x20 kernel: [<ffffffff814eccc5>] ? thread_return+0x232/0x79d kernel: [<ffffffff8126a4d9>] ? cpumask_next_and+0x29/0x50 kernel: [<ffffffff813e9c05>] ? md_super_wait+0x55/0x90 kernel: [<ffffffff81090a10>] ? autoremove_wake_function+0x0/0x40 kernel: [<ffffffff813ebf46>] ? md_update_sb+0x206/0x3f0 kernel: [<ffffffff813ee922>] ? md_check_recovery+0x3f2/0x6d0 kernel: [<ffffffffa005b129>] ? raid1d+0x49/0x1050 [raid1] kernel: [<ffffffff814ed985>] ? schedule_timeout+0x215/0x2e0 kernel: [<ffffffff814ef447>] ? _spin_unlock_irqrestore+0x17/0x20 kernel: [<ffffffff813eb336>] ? md_thread+0x116/0x150 kernel: [<ffffffff81090a10>] ? autoremove_wake_function+0x0/0x40 kernel: [<ffffffff813eb220>] ? md_thread+0x0/0x150 kernel: [<ffffffff810906a6>] ? kthread+0x96/0xa0 kernel: [<ffffffff8100c14a>] ? child_rip+0xa/0x20 kernel: [<ffffffff81090610>] ? kthread+0x0/0xa0 kernel: [<ffffffff8100c140>] ? child_rip+0x0/0x20 And something is wrong with the Named/BIND resulting in the same error for all domains: zone DOMAINEXAMPLE.com/IN: loading from master file DOMAINEXAMPLE.com failed: file not found zone DOMAINEXAMPLE.com/IN: not loaded due to errors. _default/DOMAINEXAMPLE.com/IN: file not found I'm pretty sure this is not enough information to solve the problem, but I'm willing to engage someone who can work this out for me. Any help would be greatly appreciated.

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• mysqld service crashes on restart, after importing mysqldump #innodb

  - by ubunut

  I have 2 mysql servers. Let's call them server01 & server02. Both have the same configuration: mysqladmin Ver 8.42 Distrib 5.1.61, for redhat-linux-gnu on x86_64 [client] default-character-set=utf8 [mysqld] datadir=/var/lib/mysql socket=/var/lib/mysql/mysql.sock user=mysql # Disabling symbolic-links is recommended to prevent assorted security risks symbolic-links=0 max_allowed_packet = 16M default-character-set=utf8 default-collation=utf8_unicode_ci character-set-server=utf8 collation-server=utf8_unicode_ci default-storage-engine = InnoDB innodb_data_home_dir = /var/lib/mysql innodb_log_group_home_dir = /var/lib/mysql innodb_data_file_path = ibdata1:10M:autoextend innodb_additional_mem_pool_size = 2M innodb_log_file_size = 5M innodb_log_buffer_size = 8M innodb_lock_wait_timeout = 50 innodb_flush_log_at_trx_commit = 1 innodb_buffer_pool_size = 700M table_cache = 300 thread_cache_size = 4 query_cache_size = 200m query_cache_limit = 10m [mysqld_safe] log-error=/var/log/mysqld.log pid-file=/var/run/mysqld/mysqld.pid I make a mysqldump on server01: mysqldump -uuser -ppassword --all-databases testservers.sql (most tables in these databases are innodb, some of the mysql.* tables are Innodb too) Then I import the testservers.sql on server02: mysql -uuser < testservers.sql (mysqld has been started with --skip-network). So far so good, I can login into mysql & everything seems to be ok. BUT when I exit to the shell and execute service mysqld restart, The service fails to start. stack-trace in /var/log/mysqld.log: 121022 14:53:19 mysqld_safe Starting mysqld daemon with databases from /var/lib/mysql 121022 14:53:19 [Warning] '--default-character-set' is deprecated and will be removed in a future release. Please use '--character-set-server' instead. 121022 14:53:19 [Warning] '--default-collation' is deprecated and will be removed in a future release. Please use '--collation-server' instead. 12:53:19 UTC - mysqld got signal 11 ; This could be because you hit a bug. It is also possible that this binary or one of the libraries it was linked against is corrupt, improperly built, or misconfigured. This error can also be caused by malfunctioning hardware. We will try our best to scrape up some info that will hopefully help diagnose the problem, but since we have already crashed, something is definitely wrong and this may fail. key_buffer_size=8384512 read_buffer_size=131072 max_used_connections=0 max_threads=151 thread_count=0 connection_count=0 It is possible that mysqld could use up to key_buffer_size + (read_buffer_size + sort_buffer_size)*max_threads = 338324 K bytes of memory Hope that's ok; if not, decrease some variables in the equation. Thread pointer: 0x267e630 Attempting backtrace. You can use the following information to find out where mysqld died. If you see no messages after this, something went terribly wrong... stack_bottom = 7fff3efe0be0 thread_stack 0x40000 /usr/libexec/mysqld(my_print_stacktrace+0x29) [0x84bd89] /usr/libexec/mysqld(handle_fatal_signal+0x483) [0x6a0be3] /lib64/libpthread.so.0() [0x338d60f500] /usr/libexec/mysqld(ha_resolve_by_name(THD*, st_mysql_lex_string const*)+0x81) [0x6956e1] /usr/libexec/mysqld(open_table_def(THD*, st_table_share*, unsigned int)+0xe0a) [0x60e5ba] /usr/libexec/mysqld(get_table_share(THD*, TABLE_LIST*, char*, unsigned int, unsigned int, int*)+0x20b) [0x602b0b] /usr/libexec/mysqld() [0x603597] /usr/libexec/mysqld(open_table(THD*, TABLE_LIST*, st_mem_root*, bool*, unsigned int)+0x7a1) [0x6079a1] /usr/libexec/mysqld(open_tables(THD*, TABLE_LIST**, unsigned int*, unsigned int)+0x5d0) [0x608570] /usr/libexec/mysqld(open_and_lock_tables_derived(THD*, TABLE_LIST*, bool)+0x6a) [0x60877a] /usr/libexec/mysqld(plugin_init(int*, char**, int)+0x622) [0x715af2] /usr/libexec/mysqld() [0x5bd3b2] /usr/libexec/mysqld(main+0x1b3) [0x5bfc93] /lib64/libc.so.6(__libc_start_main+0xfd) [0x338d21ecdd] /usr/libexec/mysqld() [0x5087b9] Trying to get some variables. Some pointers may be invalid and cause the dump to abort. Query (0): is an invalid pointer Connection ID (thread ID): 0 Status: NOT_KILLED The manual page at http://dev.mysql.com/doc/mysql/en/crashing.html contains information that should help you find out what is causing the crash. 121022 14:53:19 mysqld_safe mysqld from pid file /var/run/mysqld/mysqld.pid ended A typical mysqdump entry looks like this: DROP TABLE IF EXISTS `adodb_logsql`; /*!40101 SET @saved_cs_client = @@character_set_client */; /*!40101 SET character_set_client = utf8 */; CREATE TABLE `adodb_logsql` ( `id` bigint(10) unsigned NOT NULL AUTO_INCREMENT, `created` datetime NOT NULL, `sql0` varchar(250) NOT NULL DEFAULT '', `sql1` text, `params` text, `tracer` text, `timer` decimal(16,6) NOT NULL DEFAULT '0.000000', PRIMARY KEY (`id`) ) ENGINE=InnoDB DEFAULT CHARSET=utf8 COMMENT='to save some logs from ADOdb'; /*!40101 SET character_set_client = @saved_cs_client */; IF I change all occurrences of "ENGINE=InnoDB" to "ENGINE=MyISAM" before import, then the service has no problem restarting. I'm quite puzzled as to what's happening, maybe I'm just an idiot, then by all means tell me so. Any help would be greatly appreciated!

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• phpMyAdmin setup issues

  - by EquinoX

  I am trying to follow the tutorial here to setup the user and pass. It says there that "this section is only applicable if your MySQL server is running with --skip-show-database". First question is, how do I check if MySQl server is running with --skip-show-database? Is there any way I can access phpMyAdmin SQL query window without logging in? Otherwise I'd have to execute this SQL from command line. I am also getting this: Cannot load mcrypt extension. Please check your PHP configuration. I have added mcrypt.so to php.ini and doing the following command proves that I have it. [root@DT html]# rpm -qa | grep mcrypt mcrypt-2.6.8-1.el5 php-mcrypt-5.3.5-1.1.w5 libmcrypt-2.5.8-4.el5.centos [root@DT html]# php -v PHP 5.3.5 (cli) (built: Feb 19 2011 13:10:09) Copyright (c) 1997-2010 The PHP Group Zend Engine v2.3.0, Copyright (c) 1998-2010 Zend Technologies Now when I go to phpinfo() and search for mcrypt it can find it inside the Configure Command row ('--with-mcrypt=shared,/usr'). So, what to do next?. UPDATE: I didn't put extension=mcrypt.so in php.ini as it will complain the following: PHP Warning: Module 'mcrypt' already loaded in Unknown on line 0 Here's my nginx.conf: #user nobody; worker_processes 2; #error_log logs/error.log; #error_log logs/error.log notice; #error_log logs/error.log info; #pid logs/nginx.pid; events { worker_connections 1024; } http { include mime.types; default_type application/octet-stream; #log_format main '$remote_addr - $remote_user [$time_local] "$request" ' # '$status $body_bytes_sent "$http_referer" ' # '"$http_user_agent" "$http_x_forwarded_for"'; #access_log logs/access.log main; sendfile on; #tcp_nopush on; #keepalive_timeout 0; keepalive_timeout 65; gzip on; server { listen 80; root /usr/share/nginx/html; server_name localhost; #charset koi8-r; #access_log logs/host.access.log main; location / { #root html; index index.html index.htm; } #error_page 404 /404.html; # redirect server error pages to the static page /50x.html # error_page 500 502 503 504 /50x.html; location = /50x.html { #root html; } # proxy the PHP scripts to Apache listening on 127.0.0.1:80 # #location ~ \.php$ { # proxy_pass http://127.0.0.1; #} # pass the PHP scripts to FastCGI server listening on 127.0.0.1:9000 # location ~ \.php$ { #root /usr/local/nginx/html; fastcgi_pass 127.0.0.1:9000; fastcgi_index index.php; fastcgi_param SCRIPT_FILENAME /usr/share/nginx/html$fastcgi_script _name; include fastcgi_params; } # deny access to .htaccess files, if Apache's document root # concurs with nginx's one location ~ /\.ht { deny all; } } # another virtual host using mix of IP-, name-, and port-based configuration # #server { # listen 8000; # listen somename:8080; # server_name somename alias another.alias; # location / { # root html; # index index.html index.htm; # } #} # HTTPS server # #server { # listen 443; # server_name localhost; # ssl on; # ssl_certificate cert.pem; # ssl_certificate_key cert.key; # ssl_session_timeout 5m; # ssl_protocols SSLv2 SSLv3 TLSv1; # ssl_ciphers ALL:!ADH:!EXPORT56:RC4+RSA:+HIGH:+MEDIUM:+LOW:+SSLv2:+EXP; # ssl_prefer_server_ciphers on; # location / { # root html; # index index.html index.htm; # } #} }

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• Pairing Bluetooth device with PIN fails

  - by Pikaro

  I'm trying to pair my old BlackBerry 8310 to my Linux desktop (up-to-date Debian Sid, 3.15-10.dmz.1-liquorix-amd64) by using blueman and its associated tools. Scanning for the device works equally well for both sides; however, I am unable to pair the two once it comes to entering the PIN. If I scan from my PC, I have two options in blueman-manager regarding my phone: Directly selecting "pair", or selecting "setup". If I select "pair", nothing happens on my desktop, but the phone asks me to enter a PIN; if I do so, it reports that pairing has failed. During that, nothing is logged to the console. Selecting "setup" opens a configuration dialog that allows for entering or generating a PIN. Regardless, I get to a screen that tells me to enter the PIN on the phone, and at the same time, the phone pops up the equivalent dialog. This would be what one would expect to work; but whatever I enter (naturally, the same on both), both devices report that pairing has failed, and blueman-manager logs init_services (/usr/lib/python2.7/dist-packages/blueman/main/Device.py:73) Loading services org.bluez.Error.AuthenticationFailed: Authentication Failed If I instead try to pair from the phone, I cannot see any kind of reaction from my desktop - all I get is the equivalent "pairing failed" message from the BlackBerry after I entered a PIN in the dialog that pops up there. hcitool scan and hciconfig -a work without complaints, but I cannot find a way to try the pairing as a whole on the console since bluez-simple-agent seems to have been discontinued and this recommendation is everywhere on Google. hcitool cc as root opens the PIN dialog on the phone, then fails with "Input/Output error" once I enter it. The user is not permitted to execute this command. I also tried creating /usr/lib/bluetooth/<MAC>/pincodes to manually define a persistent PIN, which seems to have had no effect. The same goes for running the different commands as root, though I'm really confused about the internal structure of the Bluetooth subsystem now: They usually and inconsistently failed with Python or DBUS errors or just showed the same results. The only other Bluetooth device I have around are a pair of Creative speakers. Trying "setup" asks me to enter a key on them, which is impossible. If I try "pair", I'm asked for a PIN as I should, but no pairing takes place, and no errors appear on the console. (It just repeats their name a few times.) Interestingly, I tried that before writing my question, and nothing happened in terms of PIN questions, just like with the BlackBerry, which still shows no change. I don't think I actively changed anything since then. The BlackBerry can pair with and connect to the speakers, and everything goes as one would expect, so the problem is definitely with my desktop. So thus my questions: What is that PIN window generated by, and why does it seem to appear randomly? How can I find out what, exactly, fails after trying to add the speakers, as this may give me a clue? Is there any kind of complete log that concerns itself with Bluetooth? What data can I provide to make this more solvable?

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• Unable to make the session state request to the session state server.

  - by Angry_IT_Guru

  For about 4-5 months now, I seem to be having this sporadic issue--mainly during our busiest time of the day between 10:30-11:45AM, where all my Windows 2003 web servers in a Microsoft NLB cluster start throwing session state server errors. A sample error is below. System.Web.HttpException: Unable to make the session state request to the session state server. Please ensure that the ASP.NET State service is started and that the client and server ports are the same. If the server is on a remote machine, please ensure that it accepts remote requests by checking the value of HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\aspnet_state\Parameters\AllowRemoteConnection. If the server is on the local machine, and if the before mentioned registry value does not exist or is set to 0, then the state server connection string must use either 'localhost' or '127.0.0.1' as the server name. at System.Web.SessionState.OutOfProcSessionStateStore.MakeRequest(StateProtocolVerb verb, String id, StateProtocolExclusive exclusiveAccess, Int32 extraFlags, Int32 timeout, Int32 lockCookie, Byte[] buf, Int32 cb, Int32 networkTimeout, SessionNDMakeRequestResults& results) at System.Web.SessionState.OutOfProcSessionStateStore.SetAndReleaseItemExclusive(HttpContext context, String id, SessionStateStoreData item, Object lockId, Boolean newItem) at System.Web.SessionState.SessionStateModule.OnReleaseState(Object source, EventArgs eventArgs) at System.Web.HttpApplication.SyncEventExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() at System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) Now I'm using ASP.NET State service on a centralized back-end Windows 2003 server that all servers communicate to. I was originally using SQL Server state for a couple years as well prior to having this issue. The problem with SQL wqas that when the issue occurred, it created a blocking situation which essentially impacted all users across all servers. The product company recommended that I use the standard ASP.NET State service as that was what they technically supported. Why this would make a difference is beyond me -- but I had no choice but to try it! I have attempted to create multiple application pools, adding additional servers, chaning TCP/IP timeout from 20 to 30 seconds, and even calling Microsoft ASP.NET product support, with very little success. I even recommended that they review whether they are using read-only session state instead of read/write per page request -- as I understand that this basically causes every page to make round-trips to state server even if state isn't being used on the page. Unfortunately, the application is developed by our product company and they insist that it is something with my environment because other clients do not have these sort of issues. However, I've talked to other clients and they tell me when they've seen issues like they, they've basically had to create another web farm. This issue almost seems like I've simply reached some architectural limit within the application... Microsoft's position on the issue is that the session state needs to be reduced and the returncode being reported back from the state server indicates buffers are full. To better understand the scope of issues (rather than wait for customers to call and complain), I installed ELMAH and configured it to send me e-mails when unhandled exceptions occur. I basically get 500-1000 e-mails during the time period of high activity! If any one has any other ideas I could try or better ways to troubleshoot, I'd appreciate it.

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• I am starting to think that Prevx.com isnt a legit site...but heres my long-winded question

  - by cop1152

  I apologize in advance for the long-winded post. I posted it all because I believe its informative and may be useful. Also, I posted my question at the end. Moments ago I was RDC to a file server in my home (from inside my home). I had opened Firefox and Googled for a manufacturers website. Immediately after clicking the link, Firefox abruptly closed. This seemed odd to me to so I checked the running processes and discovered d.exe, e.exe, and f.exe running. I Googled these processes on a different machine and found them belonging to a key-logger/screen-capturer/trojan called defender.exe, which according to the Prevx lives in c:\documents and settings\user\local settings\temp. (Prevx link http://www.prevx.com/filenames/147352809685142526-X1/DEFENDER32.EXE.html) Simultaneously, an obviously-spoofed Windows Firewall popup appeared on the server asking me to click ‘yes’ to update Windows Firewall. At this time I ended all rogue processes, emptied the temp folder, removed defender.exe from startup, and checked my registry and a few other locations. Before deleting Defender.exe I noted that it was created moments ago, just before Firefox crashed. I believe that I was ‘almost’ infected with this malware. I believe that it needed me to click the phony popup in order to complete infection because it wasn’t allowed to execute processes from the temp folder. After cleaning the machine, I restarted it and have been monitoring it for over an hour. I am debating on whether or not to restore the Windows partition (a separate physical drive from the data) or to just watch it for awhle. I should mention that, because of the specs on this machine, I do not run antivirus software, but I know it well and inspect it regularly. It is a very old Compaq with a 400mhz processer and 512mb of ram. I have a static IP and the server is in the DMZ running an FTP client and some HTTP server software. All files transferred to and stored on this machine are scanned for malware before transferring. Usually the machine only runs 19 processes and performs pretty well for its intended purpose. I posted the story so that you could be aware of a possible new piece of malware and how it acts, but I also have a question or two. First, over the last few months I have noticed that PREVX is listed at the top of most of my Google searches when researching malware, especially for new or obscure malware…and they always want you to purchase something. I don’t think they are one of the top AV companies, so it seems odd that they are always the top Google result. Does anyone have any experience with any of their products? Also, what sites do you rely on for malware researching? Recently, I have found it difficult to find good info because of HijackThis-logs and other deadend info cluttering up my searches. And lastly, besides antivirus, third-party firewall, etc, what settings would you use to lock down a machine to make it more secure in instances where a stubborn admin like myself refuses to run AV? Thanks.

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• ASP.NET MVC 3 Hosting :: New Features in ASP.NET MVC 3

  - by mbridge

  Razor View Engine The Razor view engine is a new view engine option for ASP.NET MVC that supports the Razor templating syntax. The Razor syntax is a streamlined approach to HTML templating designed with the goal of being a code driven minimalist templating approach that builds on existing C#, VB.NET and HTML knowledge. The result of this approach is that Razor views are very lean and do not contain unnecessary constructs that get in the way of you and your code. ASP.NET MVC 3 Preview 1 only supports C# Razor views which use the .cshtml file extension. VB.NET support will be enabled in later releases of ASP.NET MVC 3. For more information and examples, see Introducing “Razor” – a new view engine for ASP.NET on Scott Guthrie’s blog. Dynamic View and ViewModel Properties A new dynamic View property is available in views, which provides access to the ViewData object using a simpler syntax. For example, imagine two items are added to the ViewData dictionary in the Index controller action using code like the following: public ActionResult Index() {          ViewData["Title"] = "The Title";          ViewData["Message"] = "Hello World!"; } Those properties can be accessed in the Index view using code like this: <h2>View.Title</h2> <p>View.Message</p> There is also a new dynamic ViewModel property in the Controller class that lets you add items to the ViewData dictionary using a simpler syntax. Using the previous controller example, the two values added to the ViewData dictionary can be rewritten using the following code: public ActionResult Index() {     ViewModel.Title = "The Title";     ViewModel.Message = "Hello World!"; } “Add View” Dialog Box Supports Multiple View Engines The Add View dialog box in Visual Studio includes extensibility hooks that allow it to support multiple view engines, as shown in the following figure: Service Location and Dependency Injection Support ASP.NET MVC 3 introduces improved support for applying Dependency Injection (DI) via Inversion of Control (IoC) containers. ASP.NET MVC 3 Preview 1 provides the following hooks for locating services and injecting dependencies: - Creating controller factories. - Creating controllers and setting dependencies. - Setting dependencies on view pages for both the Web Form view engine and the Razor view engine (for types that derive from ViewPage, ViewUserControl, ViewMasterPage, WebViewPage). - Setting dependencies on action filters. Using a Dependency Injection container is not required in order for ASP.NET MVC 3 to function properly. Global Filters ASP.NET MVC 3 allows you to register filters that apply globally to all controller action methods. Adding a filter to the global filters collection ensures that the filter runs for all controller requests. To register an action filter globally, you can make the following call in the Application_Start method in the Global.asax file: GlobalFilters.Filters.Add(new MyActionFilter()); The source of global action filters is abstracted by the new IFilterProvider interface, which can be registered manually or by using Dependency Injection. This allows you to provide your own source of action filters and choose at run time whether to apply a filter to an action in a particular request. New JsonValueProviderFactory Class The new JsonValueProviderFactory class allows action methods to receive JSON-encoded data and model-bind it to an action-method parameter. This is useful in scenarios such as client templating. Client templates enable you to format and display a single data item or set of data items by using a fragment of HTML. ASP.NET MVC 3 lets you connect client templates easily with an action method that both returns and receives JSON data. Support for .NET Framework 4 Validation Attributes and IvalidatableObject The ValidationAttribute class was improved in the .NET Framework 4 to enable richer support for validation. When you write a custom validation attribute, you can use a new IsValid overload that provides a ValidationContext instance. This instance provides information about the current validation context, such as what object is being validated. This change enables scenarios such as validating the current value based on another property of the model. The following example shows a sample custom attribute that ensures that the value of PropertyOne is always larger than the value of PropertyTwo: public class CompareValidationAttribute : ValidationAttribute {     protected override ValidationResult IsValid(object value,              ValidationContext validationContext) {         var model = validationContext.ObjectInstance as SomeModel;         if (model.PropertyOne > model.PropertyTwo) {            return ValidationResult.Success;         }         return new ValidationResult("PropertyOne must be larger than PropertyTwo");     } } Validation in ASP.NET MVC also supports the .NET Framework 4 IValidatableObject interface. This interface allows your model to perform model-level validation, as in the following example: public class SomeModel : IValidatableObject {     public int PropertyOne { get; set; }     public int PropertyTwo { get; set; }     public IEnumerable<ValidationResult> Validate(ValidationContext validationContext) {         if (PropertyOne <= PropertyTwo) {            yield return new ValidationResult(                "PropertyOne must be larger than PropertyTwo");         }     } } New IClientValidatable Interface The new IClientValidatable interface allows the validation framework to discover at run time whether a validator has support for client validation. This interface is designed to be independent of the underlying implementation; therefore, where you implement the interface depends on the validation framework in use. For example, for the default data annotations-based validator, the interface would be applied on the validation attribute. Support for .NET Framework 4 Metadata Attributes ASP.NET MVC 3 now supports .NET Framework 4 metadata attributes such as DisplayAttribute. New IMetadataAware Interface The new IMetadataAware interface allows you to write attributes that simplify how you can contribute to the ModelMetadata creation process. Before this interface was available, you needed to write a custom metadata provider in order to have an attribute provide extra metadata. This interface is consumed by the AssociatedMetadataProvider class, so support for the IMetadataAware interface is automatically inherited by all classes that derive from that class (notably, the DataAnnotationsModelMetadataProvider class). New Action Result Types In ASP.NET MVC 3, the Controller class includes two new action result types and corresponding helper methods. HttpNotFoundResult Action The new HttpNotFoundResult action result is used to indicate that a resource requested by the current URL was not found. The status code is 404. This class derives from HttpStatusCodeResult. The Controller class includes an HttpNotFound method that returns an instance of this action result type, as shown in the following example: public ActionResult List(int id) {     if (id < 0) {                 return HttpNotFound();     }     return View(); } HttpStatusCodeResult Action The new HttpStatusCodeResult action result is used to set the response status code and description. Permanent Redirect The HttpRedirectResult class has a new Boolean Permanent property that is used to indicate whether a permanent redirect should occur. A permanent redirect uses the HTTP 301 status code. Corresponding to this change, the Controller class now has several methods for performing permanent redirects: - RedirectPermanent - RedirectToRoutePermanent - RedirectToActionPermanent These methods return an instance of HttpRedirectResult with the Permanent property set to true. Breaking Changes The order of execution for exception filters has changed for exception filters that have the same Order value. In ASP.NET MVC 2 and earlier, exception filters on the controller with the same Order as those on an action method were executed before the exception filters on the action method. This would typically be the case when exception filters were applied without a specified order Order value. In MVC 3, this order has been reversed in order to allow the most specific exception handler to execute first. As in earlier versions, if the Order property is explicitly specified, the filters are run in the specified order. Known Issues When you are editing a Razor view (CSHTML file), the Go To Controller menu item in Visual Studio will not be available, and there are no code snippets.

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• Adding the New HTML Editor Extender to a Web Forms Application using NuGet

  - by Stephen Walther

  The July 2011 release of the Ajax Control Toolkit includes a new, lightweight, HTML5 compatible HTML Editor extender. In this blog entry, I explain how you can take advantage of NuGet to quickly add the new HTML Editor control extender to a new or existing ASP.NET Web Forms application. Installing the Latest Version of the Ajax Control Toolkit with NuGet NuGet is a package manager. It enables you to quickly install new software directly from within Visual Studio 2010. You can use NuGet to install additional software when building any type of .NET application including ASP.NET Web Forms and ASP.NET MVC applications. If you have not already installed NuGet then you can install NuGet by navigating to the following address and clicking the giant install button: http://nuget.org/ After you install NuGet, you can add the Ajax Control Toolkit to a new or existing ASP.NET Web Forms application by selecting the Visual Studio menu option Tools, Library Package Manager, Package Manager Console: Selecting this menu option opens the Package Manager Console. You can enter the command Install-Package AjaxControlToolkit in the console to install the Ajax Control Toolkit: After you install the Ajax Control Toolkit with NuGet, your application will include an assembly reference to the AjaxControlToolkit.dll and SanitizerProviders.dll assemblies: Furthermore, your Web.config file will be updated to contain a new tag prefix for the Ajax Control Toolkit controls: <configuration> <system.web> <compilation debug="true" targetFramework="4.0" /> <pages> <controls> <add tagPrefix="ajaxToolkit" assembly="AjaxControlToolkit" namespace="AjaxControlToolkit" /> </controls> </pages> </system.web> </configuration> The configuration file installed by NuGet adds the prefix ajaxToolkit for all of the Ajax Control Toolkit controls. You can type ajaxToolkit: in source view to get auto-complete in Source view. You can, of course, change this prefix to anything you want. Using the HTML Editor Extender After you install the Ajax Control Toolkit, you can use the HTML Editor Extender with the standard ASP.NET TextBox control to enable users to enter rich formatting such as bold, underline, italic, different fonts, and different background and foreground colors. For example, the following page can be used for entering comments. The page contains a standard ASP.NET TextBox, Button, and Label control. When you click the button, any text entered into the TextBox is displayed in the Label control. It is a pretty boring page: Let’s make this page fancier by extending the standard ASP.NET TextBox with the HTML Editor extender control: Notice that the ASP.NET TextBox now has a toolbar which includes buttons for performing various kinds of formatting. For example, you can change the size and font used for the text. You also can change the foreground and background color – and make many other formatting changes. You can customize the toolbar buttons which the HTML Editor extender displays. To learn how to customize the toolbar, see the HTML Editor Extender sample page here: http://www.asp.net/ajaxLibrary/AjaxControlToolkitSampleSite/HTMLEditorExtender/HTMLEditorExtender.aspx Here’s the source code for the ASP.NET page: <%@ Page Language="C#" AutoEventWireup="true" CodeBehind="Default.aspx.cs" Inherits="WebApplication1.Default" %> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head runat="server"> <title>Add Comments</title> </head> <body> <form id="form1" runat="server"> <div> <ajaxToolkit:ToolkitScriptManager ID="TSM1" runat="server" /> <asp:TextBox ID="txtComments" TextMode="MultiLine" Columns="50" Rows="8" Runat="server" /> <ajaxToolkit:HtmlEditorExtender ID="hee" TargetControlID="txtComments" Runat="server" /> <br /><br /> <asp:Button ID="btnSubmit" Text="Add Comment" Runat="server" onclick="btnSubmit_Click" /> <hr /> <asp:Label ID="lblComment" Runat="server" /> </div> </form> </body> </html> Notice that the page above contains 5 controls. The page contains a standard ASP.NET TextBox, Button, and Label control. However, the page also contains an Ajax Control Toolkit ToolkitScriptManager control and HtmlEditorExtender control. The HTML Editor extender control extends the standard ASP.NET TextBox control. The HTML Editor TargetID attribute points at the TextBox control. Here’s the code-behind for the page above:   using System; namespace WebApplication1 { public partial class Default : System.Web.UI.Page { protected void btnSubmit_Click(object sender, EventArgs e) { lblComment.Text = txtComments.Text; } } }   Preventing XSS/JavaScript Injection Attacks If you use an HTML Editor -- any HTML Editor -- in a public facing web page then you are opening your website up to Cross-Site Scripting (XSS) attacks. An evil hacker could submit HTML using the HTML Editor which contains JavaScript that steals private information such as other user’s passwords. Imagine, for example, that you create a web page which enables your customers to post comments about your website. Furthermore, imagine that you decide to redisplay the comments so every user can see them. In that case, a malicious user could submit JavaScript which displays a dialog asking for a user name and password. When an unsuspecting customer enters their secret password, the script could transfer the password to the hacker’s website. So how do you accept HTML content without opening your website up to JavaScript injection attacks? The Ajax Control Toolkit HTML Editor supports the Anti-XSS library. You can use the Anti-XSS library to sanitize any HTML content. The Anti-XSS library, for example, strips away all JavaScript automatically. You can download the Anti-XSS library from NuGet. Open the Package Manager Console and execute the command Install-Package AntiXSS: Adding the Anti-XSS library to your application adds two assemblies to your application named AntiXssLibrary.dll and HtmlSanitizationLibrary.dll. After you install the Anti-XSS library, you can configure the HTML Editor extender to use the Anti-XSS library your application’s web.config file: <?xml version="1.0" encoding="utf-8"?> <configuration> <configSections> <sectionGroup name="system.web"> <section name="sanitizer" requirePermission="false" type="AjaxControlToolkit.Sanitizer.ProviderSanitizerSection, AjaxControlToolkit"/> </sectionGroup> </configSections> <system.web> <sanitizer defaultProvider="AntiXssSanitizerProvider"> <providers> <add name="AntiXssSanitizerProvider" type="AjaxControlToolkit.Sanitizer.AntiXssSanitizerProvider"></add> </providers> </sanitizer> <compilation debug="true" targetFramework="4.0" /> <pages> <controls> <add tagPrefix="ajaxToolkit" assembly="AjaxControlToolkit" namespace="AjaxControlToolkit" /> </controls> </pages> </system.web> </configuration> Summary In this blog entry, I described how you can quickly get started using the new HTML Editor extender – included with the July 2011 release of the Ajax Control Toolkit – by installing the Ajax Control Toolkit with NuGet. If you want to learn more about the HTML Editor then please take a look at the Ajax Control Toolkit sample site: http://www.asp.net/ajaxLibrary/AjaxControlToolkitSampleSite/HTMLEditorExtender/HTMLEditorExtender.aspx

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• Enabling Kerberos Authentication for Reporting Services

  - by robcarrol

  Recently, I’ve helped several customers with Kerberos authentication problems with Reporting Services and Analysis Services, so I’ve decided to write this blog post and pull together some useful resources in one place (there are 2 whitepapers in particular that I found invaluable configuring Kerberos authentication, and these can be found in the references section at the bottom of this post). In most of these cases, the problem has manifested itself with the Login failed for User ‘NT Authority\Anonymous’ (“double-hop”) error. By default, Reporting Services uses Windows Integrated Authentication, which includes the Kerberos and NTLM protocols for network authentication. Additionally, Windows Integrated Authentication includes the negotiate security header, which prompts the client to select Kerberos or NTLM for authentication. The client can access reports which have the appropriate permissions by using Kerberos for authentication. Servers that use Kerberos authentication can impersonate those clients and use their security context to access network resources. You can configure Reporting Services to use both Kerberos and NTLM authentication; however this may lead to a failure to authenticate. With negotiate, if Kerberos cannot be used, the authentication method will default to NTLM. When negotiate is enabled, the Kerberos protocol is always used except when: Clients/servers that are involved in the authentication process cannot use Kerberos. The client does not provide the information necessary to use Kerberos. An in-depth discussion of Kerberos authentication is beyond the scope of this post, however when users execute reports that are configured to use Windows Integrated Authentication, their logon credentials are passed from the report server to the server hosting the data source. Delegation needs to be set on the report server and Service Principle Names (SPNs) set for the relevant services. When a user processes a report, the request must go through a Web server on its way to a database server for processing. Kerberos authentication enables the Web server to request a service ticket from the domain controller; impersonate the client when passing the request to the database server; and then restrict the request based on the user’s permissions. Each time a server is required to pass the request to another server, the same process must be used. Kerberos authentication is supported in both native and SharePoint integrated mode, but I’ll focus on native mode for the purpose of this post (I’ll explain configuring SharePoint integrated mode and Kerberos authentication in a future post). Configuring Kerberos avoids the authentication failures due to double-hop issues. These double-hop errors occur when a users windows domain credentials can’t be passed to another server to complete the user’s request. In the case of my customers, users were executing Reporting Services reports that were configured to query Analysis Services cubes on a separate machine using Windows Integrated security. The double-hop issue occurs as NTLM credentials are valid for only one network hop, subsequent hops result in anonymous authentication. The client attempts to connect to the report server by making a request from a browser (or some other application), and the connection process begins with authentication. With NTLM authentication, client credentials are presented to Computer 2. However Computer 2 can’t use the same credentials to access Computer 3 (so we get the Anonymous login error). To access Computer 3 it is necessary to configure the connection string with stored credentials, which is what a number of customers I have worked with have done to workaround the double-hop authentication error. However, to get the benefits of Windows Integrated security, a better solution is to enable Kerberos authentication. Again, the connection process begins with authentication. With Kerberos authentication, the client and the server must demonstrate to one another that they are genuine, at which point authentication is successful and a secure client/server session is established. In the illustration above, the tiers represent the following: Client tier (computer 1): The client computer from which an application makes a request. Middle tier (computer 2): The Web server or farm where the client’s request is directed. Both the SharePoint and Reporting Services server(s) comprise the middle tier (but we’re only concentrating on native deployments just now). Back end tier (computer 3): The Database/Analysis Services server/Cluster where the requested data is stored. In order to enable Kerberos authentication for Reporting Services it’s necessary to configure the relevant SPNs, configure trust for delegation for server accounts, configure Kerberos with full delegation and configure the authentication types for Reporting Services. Service Principle Names (SPNs) are unique identifiers for services and identify the account’s type of service. If an SPN is not configured for a service, a client account will be unable to authenticate to the servers using Kerberos. You need to be a domain administrator to add an SPN, which can be added using the SetSPN utility. For Reporting Services in native mode, the following SPNs need to be registered --SQL Server Service SETSPN -S mssqlsvc/servername:1433 Domain\SQL For named instances, or if the default instance is running under a different port, then the specific port number should be used. --Reporting Services Service SETSPN -S http/servername Domain\SSRS SETSPN -S http/servername.domain.com Domain\SSRS The SPN should be set for the NETBIOS name of the server and the FQDN. If you access the reports using a host header or DNS alias, then that should also be registered SETSPN -S http/www.reports.com Domain\SSRS --Analysis Services Service SETSPN -S msolapsvc.3/servername Domain\SSAS Next, you need to configure trust for delegation, which refers to enabling a computer to impersonate an authenticated user to services on another computer: Location Description Client 1. The requesting application must support the Kerberos authentication protocol. 2. The user account making the request must be configured on the domain controller. Confirm that the following option is not selected: Account is sensitive and cannot be delegated. Servers 1. The service accounts must be trusted for delegation on the domain controller. 2. The service accounts must have SPNs registered on the domain controller. If the service account is a domain user account, the domain administrator must register the SPNs. In Active Directory Users and Computers, verify that the domain user accounts used to access reports have been configured for delegation (the ‘Account is sensitive and cannot be delegated’ option should not be selected): We then need to configure the Reporting Services service account and computer to use Kerberos with full delegation:   We also need to do the same for the SQL Server or Analysis Services service accounts and computers (depending on what type of data source you are connecting to in your reports). Finally, and this is the part that sometimes gets over-looked, we need to configure the authentication type correctly for reporting services to use Kerberos authentication. This is configured in the Authentication section of the RSReportServer.config file on the report server. <Authentication> <AuthenticationTypes>           <RSWindowsNegotiate/> </AuthenticationTypes> <EnableAuthPersistence>true</EnableAuthPersistence> </Authentication> This will enable Kerberos authentication for Internet Explorer. For other browsers, see the link below. The report server instance must be restarted for these changes to take effect. Once these changes have been made, all that’s left to do is test to make sure Kerberos authentication is working properly by running a report from report manager that is configured to use Windows Integrated authentication (either connecting to Analysis Services or SQL Server back-end). Resources: Manage Kerberos Authentication Issues in a Reporting Services Environment http://download.microsoft.com/download/B/E/1/BE1AABB3-6ED8-4C3C-AF91-448AB733B1AF/SSRSKerberos.docx Configuring Kerberos Authentication for Microsoft SharePoint 2010 Products http://www.microsoft.com/download/en/details.aspx?displaylang=en&id=23176 How to: Configure Windows Authentication in Reporting Services http://msdn.microsoft.com/en-us/library/cc281253.aspx RSReportServer Configuration File http://msdn.microsoft.com/en-us/library/ms157273.aspx#Authentication Planning for Browser Support http://msdn.microsoft.com/en-us/library/ms156511.aspx

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• Parallelism in .NET – Part 5, Partitioning of Work

  - by Reed

  When parallelizing any routine, we start by decomposing the problem.  Once the problem is understood, we need to break our work into separate tasks, so each task can be run on a different processing element.  This process is called partitioning. Partitioning our tasks is a challenging feat.  There are opposing forces at work here: too many partitions adds overhead, too few partitions leaves processors idle.  Trying to work the perfect balance between the two extremes is the goal for which we should aim.  Luckily, the Task Parallel Library automatically handles much of this process.  However, there are situations where the default partitioning may not be appropriate, and knowledge of our routines may allow us to guide the framework to making better decisions. First off, I’d like to say that this is a more advanced topic.  It is perfectly acceptable to use the parallel constructs in the framework without considering the partitioning taking place.  The default behavior in the Task Parallel Library is very well-behaved, even for unusual work loads, and should rarely be adjusted.  I have found few situations where the default partitioning behavior in the TPL is not as good or better than my own hand-written partitioning routines, and recommend using the defaults unless there is a strong, measured, and profiled reason to avoid using them.  However, understanding partitioning, and how the TPL partitions your data, helps in understanding the proper usage of the TPL. I indirectly mentioned partitioning while discussing aggregation.  Typically, our systems will have a limited number of Processing Elements (PE), which is the terminology used for hardware capable of processing a stream of instructions.  For example, in a standard Intel i7 system, there are four processor cores, each of which has two potential hardware threads due to Hyperthreading.  This gives us a total of 8 PEs – theoretically, we can have up to eight operations occurring concurrently within our system. In order to fully exploit this power, we need to partition our work into Tasks.  A task is a simple set of instructions that can be run on a PE.  Ideally, we want to have at least one task per PE in the system, since fewer tasks means that some of our processing power will be sitting idle.  A naive implementation would be to just take our data, and partition it with one element in our collection being treated as one task.  When we loop through our collection in parallel, using this approach, we’d just process one item at a time, then reuse that thread to process the next, etc.  There’s a flaw in this approach, however.  It will tend to be slower than necessary, often slower than processing the data serially. The problem is that there is overhead associated with each task.  When we take a simple foreach loop body and implement it using the TPL, we add overhead.  First, we change the body from a simple statement to a delegate, which must be invoked.  In order to invoke the delegate on a separate thread, the delegate gets added to the ThreadPool’s current work queue, and the ThreadPool must pull this off the queue, assign it to a free thread, then execute it.  If our collection had one million elements, the overhead of trying to spawn one million tasks would destroy our performance. The answer, here, is to partition our collection into groups, and have each group of elements treated as a single task.  By adding a partitioning step, we can break our total work into small enough tasks to keep our processors busy, but large enough tasks to avoid overburdening the ThreadPool.  There are two clear, opposing goals here: Always try to keep each processor working, but also try to keep the individual partitions as large as possible. When using Parallel.For, the partitioning is always handled automatically.  At first, partitioning here seems simple.  A naive implementation would merely split the total element count up by the number of PEs in the system, and assign a chunk of data to each processor.  Many hand-written partitioning schemes work in this exactly manner.  This perfectly balanced, static partitioning scheme works very well if the amount of work is constant for each element.  However, this is rarely the case.  Often, the length of time required to process an element grows as we progress through the collection, especially if we’re doing numerical computations.  In this case, the first PEs will finish early, and sit idle waiting on the last chunks to finish.  Sometimes, work can decrease as we progress, since previous computations may be used to speed up later computations.  In this situation, the first chunks will be working far longer than the last chunks.  In order to balance the workload, many implementations create many small chunks, and reuse threads.  This adds overhead, but does provide better load balancing, which in turn improves performance. The Task Parallel Library handles this more elaborately.  Chunks are determined at runtime, and start small.  They grow slowly over time, getting larger and larger.  This tends to lead to a near optimum load balancing, even in odd cases such as increasing or decreasing workloads.  Parallel.ForEach is a bit more complicated, however. When working with a generic IEnumerable<T>, the number of items required for processing is not known in advance, and must be discovered at runtime.  In addition, since we don’t have direct access to each element, the scheduler must enumerate the collection to process it.  Since IEnumerable<T> is not thread safe, it must lock on elements as it enumerates, create temporary collections for each chunk to process, and schedule this out.  By default, it uses a partitioning method similar to the one described above.  We can see this directly by looking at the Visual Partitioning sample shipped by the Task Parallel Library team, and available as part of the Samples for Parallel Programming.  When we run the sample, with four cores and the default, Load Balancing partitioning scheme, we see this: The colored bands represent each processing core.  You can see that, when we started (at the top), we begin with very small bands of color.  As the routine progresses through the Parallel.ForEach, the chunks get larger and larger (seen by larger and larger stripes). Most of the time, this is fantastic behavior, and most likely will out perform any custom written partitioning.  However, if your routine is not scaling well, it may be due to a failure in the default partitioning to handle your specific case.  With prior knowledge about your work, it may be possible to partition data more meaningfully than the default Partitioner. There is the option to use an overload of Parallel.ForEach which takes a Partitioner<T> instance.  The Partitioner<T> class is an abstract class which allows for both static and dynamic partitioning.  By overriding Partitioner<T>.SupportsDynamicPartitions, you can specify whether a dynamic approach is available.  If not, your custom Partitioner<T> subclass would override GetPartitions(int), which returns a list of IEnumerator<T> instances.  These are then used by the Parallel class to split work up amongst processors.  When dynamic partitioning is available, GetDynamicPartitions() is used, which returns an IEnumerable<T> for each partition.  If you do decide to implement your own Partitioner<T>, keep in mind the goals and tradeoffs of different partitioning strategies, and design appropriately. The Samples for Parallel Programming project includes a ChunkPartitioner class in the ParallelExtensionsExtras project.  This provides example code for implementing your own, custom allocation strategies, including a static allocator of a given chunk size.  Although implementing your own Partitioner<T> is possible, as I mentioned above, this is rarely required or useful in practice.  The default behavior of the TPL is very good, often better than any hand written partitioning strategy.

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• Parallelism in .NET – Part 15, Making Tasks Run: The TaskScheduler

  - by Reed

  In my introduction to the Task class, I specifically made mention that the Task class does not directly provide it’s own execution.  In addition, I made a strong point that the Task class itself is not directly related to threads or multithreading.  Rather, the Task class is used to implement our decomposition of tasks.  Once we’ve implemented our tasks, we need to execute them.  In the Task Parallel Library, the execution of Tasks is handled via an instance of the TaskScheduler class. The TaskScheduler class is an abstract class which provides a single function: it schedules the tasks and executes them within an appropriate context.  This class is the class which actually runs individual Task instances.  The .NET Framework provides two (internal) implementations of the TaskScheduler class. Since a Task, based on our decomposition, should be a self-contained piece of code, parallel execution makes sense when executing tasks.  The default implementation of the TaskScheduler class, and the one most often used, is based on the ThreadPool.  This can be retrieved via the TaskScheduler.Default property, and is, by default, what is used when we just start a Task instance with Task.Start(). Normally, when a Task is started by the default TaskScheduler, the task will be treated as a single work item, and run on a ThreadPool thread.  This pools tasks, and provides Task instances all of the advantages of the ThreadPool, including thread pooling for reduced resource usage, and an upper cap on the number of work items.  In addition, .NET 4 brings us a much improved thread pool, providing work stealing and reduced locking within the thread pool queues.  By using the default TaskScheduler, our Tasks are run asynchronously on the ThreadPool. There is one notable exception to my above statements when using the default TaskScheduler.  If a Task is created with the TaskCreationOptions set to TaskCreationOptions.LongRunning, the default TaskScheduler will generate a new thread for that Task, at least in the current implementation.  This is useful for Tasks which will persist for most of the lifetime of your application, since it prevents your Task from starving the ThreadPool of one of it’s work threads. The Task Parallel Library provides one other implementation of the TaskScheduler class.  In addition to providing a way to schedule tasks on the ThreadPool, the framework allows you to create a TaskScheduler which works within a specified SynchronizationContext.  This scheduler can be retrieved within a thread that provides a valid SynchronizationContext by calling the TaskScheduler.FromCurrentSynchronizationContext() method. This implementation of TaskScheduler is intended for use with user interface development.  Windows Forms and Windows Presentation Foundation both require any access to user interface controls to occur on the same thread that created the control.  For example, if you want to set the text within a Windows Forms TextBox, and you’re working on a background thread, that UI call must be marshaled back onto the UI thread.  The most common way this is handled depends on the framework being used.  In Windows Forms, Control.Invoke or Control.BeginInvoke is most often used.  In WPF, the equivelent calls are Dispatcher.Invoke or Dispatcher.BeginInvoke. As an example, say we’re working on a background thread, and we want to update a TextBlock in our user interface with a status label.  The code would typically look something like: // Within background thread work... string status = GetUpdatedStatus(); Dispatcher.BeginInvoke(DispatcherPriority.Normal, new Action( () => { statusLabel.Text = status; })); // Continue on in background method .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } This works fine, but forces your method to take a dependency on WPF or Windows Forms.  There is an alternative option, however.  Both Windows Forms and WPF, when initialized, setup a SynchronizationContext in their thread, which is available on the UI thread via the SynchronizationContext.Current property.  This context is used by classes such as BackgroundWorker to marshal calls back onto the UI thread in a framework-agnostic manner. The Task Parallel Library provides the same functionality via the TaskScheduler.FromCurrentSynchronizationContext() method.  When setting up our Tasks, as long as we’re working on the UI thread, we can construct a TaskScheduler via: TaskScheduler uiScheduler = TaskScheduler.FromCurrentSynchronizationContext(); We then can use this scheduler on any thread to marshal data back onto the UI thread.  For example, our code above can then be rewritten as: string status = GetUpdatedStatus(); (new Task(() => { statusLabel.Text = status; })) .Start(uiScheduler); // Continue on in background method This is nice since it allows us to write code that isn’t tied to Windows Forms or WPF, but is still fully functional with those technologies.  I’ll discuss even more uses for the SynchronizationContext based TaskScheduler when I demonstrate task continuations, but even without continuations, this is a very useful construct. In addition to the two implementations provided by the Task Parallel Library, it is possible to implement your own TaskScheduler.  The ParallelExtensionsExtras project within the Samples for Parallel Programming provides nine sample TaskScheduler implementations.  These include schedulers which restrict the maximum number of concurrent tasks, run tasks on a single threaded apartment thread, use a new thread per task, and more.

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