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• OpenVPN bad source address from client

  - by Bogdan

  I have one problem with OpenVPN. There are a lot drops records in the openvpn log file on the server: Mon Oct 22 10:14:41 2012 us=726541 laptop/???:1194 MULTI: bad source address from client [192.168.1.107], packet dropped grep -E "^[a-z]" server.conf ----- port 1194 proto udp dev tun ca data/ca.crt cert data/server.crt key data/server.key dh data/dh1024.pem tls-server tls-auth data/ta.key 0 remote-cert-tls client cipher AES-256-CBC tun-mtu 1200 server 10.10.10.0 255.255.255.0 ifconfig-pool-persist ipp.txt push "redirect-gateway def1 bypass-dhcp" push "dhcp-option DNS 8.8.8.8" client-to-client client-config-dir /etc/openvpn/ccd route 10.10.10.0 255.255.255.0 keepalive 10 120 comp-lzo persist-key persist-tun max-clients 5 status /var/log/status-openvpn.log log /var/log/openvpn.log verb 4 auth-user-pass-verify /etc/openvpn/verify.sh via-file tmp-dir /tmp script-security 2 ----- cat ccd/laptop ----- iroute 10.10.10.0 255.255.255.0 ----- cat client.conf ----- remote server ip 1194 client dev tun ping 10 comp-lzo proto udp tls-client tls-auth data/ta.key 1 pkcs12 data/vpn.laptop.p12 remote-cert-tls server #ns-cert-type server persist-key persist-tun cipher AES-256-CBC verb 3 pull auth-user-pass /home/user/.openvpn/users.db ----- According to "Jan Just Keijser - OpenVPN 2 Cookbook" root of the problem is incorrect config options.see the screenshot But, as you see, my config has such options. Could you please help me to solve this problem. @week Verb leverl=6; client log. Mon Oct 22 16:06:02 2012 do_ifconfig, tt->ipv6=0, tt->did_ifconfig_ipv6_setup=0 Mon Oct 22 16:06:02 2012 /sbin/ifconfig tun0 10.10.10.3 pointopoint 10.10.10.5 mtu 1500 Mon Oct 22 16:06:02 2012 /sbin/route add -net xxxx netmask 255.255.255.255 gw 192.168.1.1 Mon Oct 22 16:06:02 2012 /sbin/route add -net 0.0.0.0 netmask 128.0.0.0 gw 10.10.10.5 Mon Oct 22 16:06:02 2012 /sbin/route add -net 128.0.0.0 netmask 128.0.0.0 gw 10.10.10.5 Mon Oct 22 16:06:02 2012 Initialization Sequence Completed cat ccd/latop iroute 10.10.10.0 255.255.255.0 ifconfig-push 10.10.10.3 10.10.10.5

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• ESX Scheduler and NUMA issue

  - by babyg_wc

  On our 24 core bl685 (4sockets x 6core), we find that NUMA nodes 0 and 1 are pretty busy (unfortunately resulting in elevated cpu ready times on the VMS), whilst NUMA nodes 2 and 3 are almost unused. I thought this just maybe a ESX4 U1 issue, so I had a colleague with a 32 core (dl785) farm investigate, and it seems that his last 3 or 4 NUMA nodes are also not really being utilised. ESX seems to have a weakness when it comes to balancing lightly loaded NUMA boxes, Im going to enabled node interleaving in the BIOS and see if the scheduler balancers across all 24 cores, instead of just 12!... For those of you with large core counts, I would suggest you fire up you viclient, and check Physical CPU useage (or esxtop), I would be interested to hear what your results are. Please note, that its only the lightly loaded (eg less than 30% cpu load on the esx host) that seems to have the biggest issue with load imbalance. Thoughts/comments. PS ive logged a SR with vmware to assist, also the other "problem" could be that we have 128gb of ram in each host, and therefore the scheduler sees no good reason why it shouldnt try and cram all vms's into the first two NUMA nodes, as we only have around 50gb of ram worth of vms on each host...

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• Debugging "clogged" TCP connections

  - by Nikratio

  I'm having trouble with an internet connection that seems to randomly "freeze" arbitrary tcp connections. The connections stay established, but no data is coming through. When this happens, netstat still shows the connection status as ESTABLISHED on both the local computer: Proto Recv-Q Send-Q Local Address Foreign Address State PID/Program name Timer tcp 0 53 192.168.0.10:41129 173.255.235.238:143 ESTABLISHED 8219/gnutls-cli on (79.31/13/0) ..and the remote server: Proto Recv-Q Send-Q Local Address Foreign Address State PID/Program name Timer tcp 0 0 173.255.235.238:143 68.5.174.98:41129 ESTABLISHED 5303/imapd off (0.00/0/0) However, it seems that no data at all is transferred. If I run strace on the local and remote process, both just show a repeating sequence of select calls (with different fds of course), e.g. select(6, [0 5], NULL, NULL, {0, 50000}) = 0 (Timeout) select(6, [0 5], NULL, NULL, {0, 50000}) = 0 (Timeout) select(6, [0 5], NULL, NULL, {0, 50000}) = 0 (Timeout) The internet connection overall does not seem affected, I can still establish new connections to the same service on the same server without any problems. However, the affected local applications seem to be unaware of the problem and just hang. When I look at a packet capture of this connection on the client side, the last thing that happens is that the client transmits some data, then nothing happens for about 1100 seconds, and then several TCP Retransmission requests go out, with intervals increasing from 4 seconds to 130 seconds. No activity is captured after that. After about 10 minutes, the connection on the remote end disappears from the netstat (I wasn't able to catch any intermediate state), but still stays ESTABLISHED on the local end. Finally, after some more minutes, the local application aborts with a timeout and disappears from the local netstat output as well. Does anyone have a suggestion of how I could debug this further to find out where the problem lies and how to fix it? Additionaly and/or as a temporary workaround: is is there some way to globally reduce the timeout on client and/or server to reduce the time before the local application aborts?

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• Use one NIC to create multiple interfaces for Linux KVM

  - by Phanto

  I am working on a thesis research project, and I am having some difficulty figuring out how to make one NIC spawn several "bridge" interfaces such that each KVM VM can be seen on the local network. I am very new to KVM, and am still exploring what it can do. Below is the scenario that I am attempting to make (on a CentOS/RHEL 6 system): Linux KVM Host has 1 NIC (eth0) connected to a switch. Create multiple "bridge" or equivalent interfaces that are spawned off of eth0 that would provide a unique IP for each VM. This is so that each VM can communicate with other hosts on the network, and that other hosts on the network can communicate with the VM. IMPORTANT: I would like iptables on the KVM host to be able to manipulate/control/restrict the traffic that would be sent on those "bridge" interfaces. I would like to create a minimum of three VM's, each using their own unique "bridge" interfaces. I have previously made a br0 interface off of eth0, but unfortunately, I am unable to add any more to it. It appears that you can only bridge 1 interface to the NIC. I would like to bridge many to one. Would a tap device be able to do this? If so, how would it be set up? Effectively, I am attempting to replicate what can easily be created with VirtualBox on Windows, where each VM is given a "bridged" interface, and can live on the network. I want to achieve this very same thing with Linux KVM. Thank You EDIT: To be more descriptive, I want to achieve something that looks like this: This can be found on this page: http://en.gentoo-wiki.com/wiki/KVM#Networking_2 HOST +---------------+ | | KVM GUEST1 | | +--------------+ | +------+ | | | LAN ---+--- eth0 | +--+---+---- nic0 | KVM GUEST2 | | tap0----+ | |192.168.1.13 | +--------------+ | | tap1----+ | +--------------+ | | | +------+ | | | | | br0 +--+----------------------+---- nic0 | |192.168.1.12 | |192.168.1.14 | +---------------+ +--------------+

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• VMware and Windows Activation

  - by Peter M

  Yesterday I installed Slysoft's Virtual CloneDrive in order to mount an iso for some software installation on my host system (XP Pro SP3) This morning I fired up VMware and made a linked clone of an existing XP vm in order to do some software testing. This is the sort of thing that I do all the time, and the base XP vm that I clone was activated a long long time ago. The surprise today was that the newly cloned vm was no longer activated and XP cited major changes in hardware as the reason. I repeated the test with a full clone of the base system and got the same message. I then started up my base vm and it seemed to be activated, yet another vm (which I fully cloned from the base vm a long time ago) now started reporting that XP was not activated. At this point I guessed that Virtual DriveClone might have been the source of my hardware differences so I uninstalled it and rebooted. After this I made a new linked clone and full clone of the base vm and XP did not complain about not being activated. So I seem to be back to where I was before installing Virtual DriveClone with the exception that that one particular XP vm continues to complain about activation (even though 4 or 5 other XP vm's are fat and happy) Now to my questions: Why would adding Virtual CloneDrive to the host system affect XP activation on the vm's? From their point of view I would have thought that the environment had not changed as I had not enabled any new hard drives in their systems. Or is adding a hard drive to the host system enough to upset XP activation? Since this event, one of my fully cloned vm's is still reporting that XP is not activated even though I have removed Virtual CloneDrive. Is there anyway to convince XP that it is on the same system as yesterday? Or are my only options to do an activation or restore the vm from a previous backup?

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• How to run a website domain without redirecting if IP is already used for another website? [duplicate]

  - by SSpoke

  This question already has an answer here: Hosting multiple distinct folders for distinct domains 1 answer I bought a VPS Host that gave me only 1 IP Address which I used on my first domain name and it works without any problems. Now my second domain name I can't use the same ip address as it points to the first domain name. So I figured my only option was to use a GoDaddy hosted iframe redirection which redirects to a sub folder on my first domain which worked so far. Now I'm trying to load paypal from <?php headers() ?> and I get a permission error because of that iframe Refused to display 'https://www.paypal.com/cgi-bin/webscr?notify_url=&cmd=_cart&upload=1&business=removed&address_override=1' in a frame because it set 'X-Frame-Options' to 'SAMEORIGIN'. How do I avoid the Iframe solution for my second domain while not messing up my first domain? Somebody I forgot once told me it doesn't matter if you have 1 IP Address you could host multiple websites on it? how it that possible the DNS doesn't seem to work off ports afaik, yes I could host multiple websites on different folders but that's not what I call hosting a real website it has to be pointed by a domain name, so this iframe issue doesn't happen My server configuration is httpd (apache) that comes with CentOS 6 (Linux) operating system

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• How can I connect integrated webcam with virtualbox

  - by Mike Stumpf

  I am trying to use a Windows XP VM for VirtualBox on my Windows 8.1 laptop. I have tried the usual attaching USB device but I get an error saying "USB device is busy with previous request". My webcam is not active in any applications and this happens after a clean reboot of the host, the guest, and VirtualBox. Here are the details: Host -HP Pavilion 17 Notebook PC (stock) -Windows 8.1 -AMD A10-5750M APU -HP Truevision HD (integrated webcam) VM I got the VM here: http://www.modern.ie/en-us/virtualization-tools VirtualBox -VirtualBox 4.3.12 installed -VirtualBox Extension pack installed -Guest additions are installed for 4.3.12 -Enable USB Controller is checked -It does not matter if enable 2.0 controller is checked or not -It does not matter if a USB device filter is set up for the webcam or not -Here is the error message: Failed to attach the USB device DDFEQ01G45BFBV HP Truevision HD [0004] to the virtual machine IE8 - WinXP. USB device 'DDFEQ01G45BFBV HP Truevision HD' with UUID {7a2e2a45-974d-482b-9b4e-9f9abbcd0ebb} is busy with a previous request. Please try again later. Result Code: E_INVALIDARG (0x80070057) Component: HostUSBDevice Interface: IHostUSBDevice {173b4b44-d268-4334-a00d-b6521c9a740a} Callee: IConsole {8ab7c520-2442-4b66-8d74-4ff1e195d2b6} I read on some VirtualBox forums that disabling USB 2.0 support in the host BIOS solved their issue but I wanted to know if there were any other ideas before I muck around in there. Thanks

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• Using IIS7 as a reverse proxy

  - by Eric Petroelje

  I'm setting up a server at home to host a few small websites. One of them is .NET based and needs IIS, the others are PHP based and need Apache. So, I have both IIS 7 and Apache 2.2.x installed on my server with IIS on port 80 and Apache running on port 8080. I would like to set up IIS to work as a reverse proxy, forwarding the requests for the Apache sites to port 8080 and serving the requests for the .NET site itself based on the host headers. Like this: www.mydotnetsite.com/* -> IIS -> serve from IIS www.myapachesite.com/* -> IIS -> forward to apache on port 8080 www.myothersite.com/* -> IIS -> forward to apache on port 8080 I did a bit of googling and it seemed like the Application Request Routing feature would do what I needed, but I can't seem to get it to work the way I want it to. I can get it to forward ALL traffic to the Apache server and I can get it to forward traffic with a specific URL pattern to the Apache server, but I can't seem to get it to forward based on the host headers (e.g. "forward all requests for www.apachesite.com - localhost:8080") So the question is, how would I go about configuring ARR to do this? Or do I need a different tool? I'm also open to using Apache as the reverse proxy and forwarding the .NET site requests to IIS instead if that's easier (running Apache on port 80 and IIS on 8080).

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• Upgrade an Ubuntu 8.04 installation with VMware Server 1.0.8 and lots of guest OSes to Something Els

  - by Glyph

  I have an Ubuntu 8.04 (Hardy Heron) host machine which is running a whole slew of virtual machines in VMWare Server 1.0.8. Among other guest OSes, there is every release version of Ubuntu since 6.06, OpenSolaris 2009.06, and Windows XP. Right now I access these VMs from a variety of client OSes as well; Linux and Windows via the VMWare server console, and MacOS via X-forwarding the host machine's server console. I'd like to upgrade the host to Ubuntu 10.04 (Lucid Lynx), but from what I can tell, getting VMWare Server 1.x to work on a more recent version of Linux is a real pain. While VMware Server 2.x is a bit easier, it's still not packaged as Debian packages, so installing security updates is a big chore. As long as I'm upgrading anyway, I'd like to move to a virtualization solution that will allow me to automate applying updates. The options that I'm aware of right now are KVM (managed via virt-manager) and VirtualBox (as managed by its own tools or via its own libvirt bindings), but I'm open to other suggestions. For each option, I'd like to know how do I convert my guest images to the new format? am I going to have to re-activate my Windows guests (alternatively, "If the virtual hardware is different by default, can I avoid re-activation by changing some virtualization configuration to provide me with more similar virtual hardware") what are the management options like for each client OS (mac, linux, windows)? Thanks.

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• What command should be used to connect via SSH through squid proxy?

  - by Raul Cardoso

  I have set up a Squid HTTP Proxy (in centOS) and intended to use it also for ssh connections. Managed to configure putty (in a windows client) to use this proxy while connecting by ssh. Confirmed in the "target host" that the ssh connection was coming from Proxy server ip instead of the windows client IP. Used: targethost: 22 for ssh proxyserv: 3128 for proxy (along with proxy credentials) I'm now having problems connecting to the "target host" using Ubuntu and the same proxy server. I have tried the following: me@mycomp:~$ connect-proxy -H test@proxyserv:3128 targethost 22 Enter proxy authentication password for test@proxyserv: SSH-2.0-OpenSSH_6.2p2 Ubuntu-6 It hangs in last line, expecting some input. All attempts resulted in a "Protocol mismatch." error. Putty successfully connects to the http proxy and sends credentials, showing me ssh login right away. - How to do (with commands in Ubuntu) the same putty does? - Is there any other way than connect-proxy command to do this? Edit: Also tried the following with same result ("Protocol mismatch") me@mycomp:~$ connect-proxy -H test@proxyserv:3128 targethost 22 ssh -l myshel_login Thanks in advance Edit: Solution details (thanks to NickW pointing the right way) installed corkscrew and added to ssh_config Host targethost ProxyCommand corkscrew proxyserv 3128 %h %p /etc/ssh/proxypass created proxypass file login:password Restarted ssh and used a simple ssh command ssh mylogin@targethost (ssh password was asked as usual)

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• Running WordPress and Ghost on Apache with mod_proxy

  - by Jack Perry

  I currently have three WordPress sites hosted on Apache with virtual host files to direct the right domain to the right DocumentRoot. Ghost (node.js) just came out and I've wanted to tinker with it and just play around on one of my spare domains. I'm not really interested in moving over to nginx so I'm trying to get Ghost working on Apache via mod_proxy. I've managed to get Ghost working on my spare domain, but I think there's a problem with my virtual host files, as all of my other domains start pointing to Ghost as well. Here are two virtual host files, one for my main WordPress site that works fine, and the second for Ghost. Domains removed and replaced with DOMAIN and DOMAIN2. DOMAIN <VirtualHost *:80> ServerAdmin webmaster@localhost ServerName DOMAIN.com ServerAlias www.DOMAIN.com DocumentRoot /var/www/DOMAIN.com/public_html <Directory /> Options FollowSymLinks AllowOverride All </Directory> <Directory /var/www/DOMAIN.com/public_html> Options Indexes FollowSymLinks MultiViews AllowOverride All Order allow,deny allow from all </Directory> ScriptAlias /cgi-bin/ /usr/lib/cgi-bin/ <Directory "/usr/lib/cgi-bin"> AllowOverride None Options +ExecCGI -MultiViews +SymLinksIfOwnerMatch Order allow,deny Allow from all </Directory> ErrorLog ${APACHE_LOG_DIR}/error.log # Possible values include: debug, info, notice, warn, error, crit, # alert, emerg. LogLevel warn CustomLog ${APACHE_LOG_DIR}/access.log combined Alias /doc/ "/usr/share/doc/" <Directory "/usr/share/doc/"> Options Indexes MultiViews FollowSymLinks AllowOverride None Order deny,allow Deny from all Allow from 127.0.0.0/255.0.0.0 ::1/128 </Directory> </VirtualHost> DOMAIN2 <VirtualHost IP:80> ServerAdmin EMAIL ServerName DOMAIN2.com ServerAlias www.DOMAIN2.com ProxyPreserveHost on ProxyPass / http://IP:2368/ </VirtualHost> I get the feeling I'm not working with virtual hosts or mod_proxy right, and Google-fu has let me down after many suggested attempts. Any ideas? Thanks!

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• Windows 8 Internet Explorer proxy automation script

  - by Stefan Bollmann

  Similar to this post, I'd like to change my proxy settings using a script. However, it fails. When I am behind the proxy, IE does not connect to the internet. Here I try the first solution from craig: function FindProxyForURL(url, host) { if (isInNet(myIpAddress(), "myactualip", "myactualsubnetip")) return "PROXY proxyasshowninpicture:portihavetouseforthisproxy_see_picture"; else return "DIRECT"; } Also this test, where isInNet should surely return true does not help: function FindProxyForURL(url, host) { if (isInNet("myactualip", "myactualip", "myactualsubnetip")) return "PROXY proxyasshowninpicture:portihavetouseforthisproxy_see_picture"; else return "DIRECT"; } **This script is saved as proxy.pac in c:\windows and my configuration is* in LAN settings: No automatically detected settings, yes, use automatic config script: file://c:/windows/proxy.pac No proxy server. *(i am not allowed to post screenshots..) So, what am I doing wrong? ---------------- update -------------- However, when I set up a proxy in my LAN configurations: IE -> Internet Options -> Connections -> LAN Settings check: Use a proxy Server for your LAN Address: <a pingable proxy> Port: <portnr> everything is fine for this environment. Now I try a simpler script like function FindProxyForURL(url, host) { return "PROXY <pingable proxy>:<portnr>; DIRECT"; } With a configuration described above** I am not able to get through the proxy.

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• Choose identity from ssh-agent by file name

  - by leoluk

  Problem: I have some 20-30 ssh-agent identities. Most servers refuse authentication with Too many failed authentications, as SSH usually won't let me try 20 different keys to log in. At the moment, I am specifying the identity file for every host manually, using the IdentityFile and the IdentitiesOnly directive, so that SSH will only try one key file, which works. Unfortunately, this stops working as soon as the original keys aren't available anymore. ssh-add -l shows me the correct paths for every key file, and they match with the paths in .ssh/config, but it doesn't work. Apparently, SSH selects the indentity by public key signature and not by file name, which means that the original files have to be available so that SSH can extract the public key. There are two problems with this: it stops working as soon as I unplug the flash drive holding the keys it renders agent forwarding useless as the key files aren't available on the remote host Of course, I could extract the public keys from my identity files and store them on my computer, and on every remote computer I usually log into. This doesn't looks like a desirable solution, though. What I need is a possibility to select an identity from ssh-agent by file name, so that I can easily select the right key using .ssh/config or by passing -i /path/to/original/key, even on a remote host I SSH'd into. It would be even better if I could "nickname" the keys so that I don't even have to specify the full path.

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• pptpd-logwtmp.so config wrong ip address

  - by rgc

  i have setup a pptp vpn on ubuntu 10.04, and i config local ip address , remote ip address as following: local IP address 10.0.30.100 remote IP address 192.168.13.100 after i use windows to connect to vpn server in windows , i only could send packets, can not receive any packets. i also check the pptp log in ubuntu server, and find this strange thing rcvd [IPCP ConfAck id=0x1 <compress VJ 0f 01> <addr 10.0.30.100>] rcvd [IPCP ConfReq id=0x2 <compress VJ 0f 01> <addr 192.168.13.100> <ms-dns1 202.119.32.6> <ms-dns2 202.119.32.12>] sent [IPCP ConfAck id=0x2 <compress VJ 0f 01> <addr 192.168.13.100> <ms-dns1 202.119.32.6> <ms-dns2 202.119.32.12>] Cannot determine ethernet address for proxy ARP local IP address 10.0.30.100 remote IP address 192.168.13.100 pptpd-logwtmp.so ip-up ppp0 **172.25.146.174** i did not set 172.25.146.174, it should be 192.168.13.100, can anyone tell me what should i do to fix this problem?

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• GRE Tunnel over IPsec with Loopback

  - by Alek

  Hello, I'm having a really hard time trying to estabilish a VPN connection using a GRE over IPsec tunnel. The problem is that it involves some sort of "loopback" connection which I don't understand -- let alone be able to configure --, and the only help I could find is related to configuring Cisco routers. My network is composed of a router and a single host running Debian Linux. My task is to create a GRE tunnel over an IPsec infrastructure, which is particularly intended to route multicast traffic between my network, which I am allowed to configure, and a remote network, for which I only bear a form containing some setup information (IP addresses and phase information for IPsec). For now it suffices to estabilish a communication between this single host and the remote network, but in the future it will be desirable for the traffic to be routed to other machines on my network. As I said this GRE tunnel involves a "loopback" connection which I have no idea of how to configure. From my previous understanding, a loopback connection is simply a local pseudo-device used mostly for testing purposes, but in this context it might be something more specific that I do not have the knowledge of. I have managed to properly estabilish the IPsec communication using racoon and ipsec-tools, and I believe I'm familiar with the creation of tunnels and addition of addresses to interfaces using ip, so the focus is on the GRE step. The worst part is that the remote peers do not respond to ping requests and the debugging of the general setup is very difficult due to the encrypted nature of the traffic. There are two pairs of IP addresses involved: one pair for the GRE tunnel peer-to-peer connection and one pair for the "loopback" part. There is also an IP range involved, which is supposed to be the final IP addresses for the hosts inside the VPN. My question is: how (or if) can this setup be done? Do I need some special software or another daemon, or does the Linux kernel handle every aspect of the GRE/IPsec tunneling? Please inform me if any extra information could be useful. Any help is greatly appreciated.

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• FreeBSD 8.1 unstable network connection

  - by frankcheong

  I have three FreeBSD 8.1 running on three different hardware and therefore consist of different network adapter as well (bce, bge and igb). I found that the network connection is kind of unstable which I have tried to scp some 10MB file and found that I cannot always get the files completed successfully. I have further checked with my network admin and he claim that the problem is being caused by the network driver which cannot support the load whereby he tried to ping using huge packet size (around 15k) and my server will drop packet consistently at a regular interval. I found that this statement may not be valid since the three server is using three different network drive and it would be quite impossible that the same problem is being caused by three different network adapter and thus different network driver. Since then I have tried to tune up the performance by playing around with the /etc/sysctl.conf figures with no luck. kern.ipc.somaxconn=1024 kern.ipc.shmall=3276800 kern.ipc.shmmax=1638400000 # Security net.inet.ip.redirect=0 net.inet.ip.sourceroute=0 net.inet.ip.accept_sourceroute=0 net.inet.icmp.maskrepl=0 net.inet.icmp.log_redirect=0 net.inet.icmp.drop_redirect=1 net.inet.tcp.drop_synfin=1 # Security net.inet.udp.blackhole=1 net.inet.tcp.blackhole=2 # Required by pf net.inet.ip.forwarding=1 #Network Performance Tuning kern.ipc.maxsockbuf=16777216 net.inet.tcp.rfc1323=1 net.inet.tcp.sendbuf_max=16777216 net.inet.tcp.recvbuf_max=16777216 # Setting specifically for 1 or even 10Gbps network net.local.stream.sendspace=262144 net.local.stream.recvspace=262144 net.inet.tcp.local_slowstart_flightsize=10 net.inet.tcp.nolocaltimewait=1 net.inet.tcp.mssdflt=1460 net.inet.tcp.sendbuf_auto=1 net.inet.tcp.sendbuf_inc=16384 net.inet.tcp.recvbuf_auto=1 net.inet.tcp.recvbuf_inc=524288 net.inet.tcp.sendspace=262144 net.inet.tcp.recvspace=262144 net.inet.udp.recvspace=262144 kern.ipc.maxsockbuf=16777216 kern.ipc.nmbclusters=32768 net.inet.tcp.delayed_ack=1 net.inet.tcp.delacktime=100 net.inet.tcp.slowstart_flightsize=179 net.inet.tcp.inflight.enable=1 net.inet.tcp.inflight.min=6144 # Reduce the cache size of slow start connection net.inet.tcp.hostcache.expire=1 Our network admin also claim that they see quite a lot of network up and down from their cisco switch log while I cannot find any up down message inside the dmesg. Have further checked the netstat -s but dont have concrete idea. tcp: 133695291 packets sent 39408539 data packets (3358837321 bytes) 61868 data packets (89472844 bytes) retransmitted 24 data packets unnecessarily retransmitted 0 resends initiated by MTU discovery 50756141 ack-only packets (2148 delayed) 0 URG only packets 0 window probe packets 4372385 window update packets 39781869 control packets 134898031 packets received 72339403 acks (for 3357601899 bytes) 190712 duplicate acks 0 acks for unsent data 59339201 packets (3647021974 bytes) received in-sequence 114 completely duplicate packets (135202 bytes) 27 old duplicate packets 0 packets with some dup. data (0 bytes duped) 42090 out-of-order packets (60817889 bytes) 0 packets (0 bytes) of data after window 0 window probes 3953896 window update packets 64181 packets received after close 0 discarded for bad checksums 0 discarded for bad header offset fields 0 discarded because packet too short 45192 discarded due to memory problems 19945391 connection requests 1323420 connection accepts 0 bad connection attempts 0 listen queue overflows 0 ignored RSTs in the windows 21133581 connections established (including accepts) 21268724 connections closed (including 32737 drops) 207874 connections updated cached RTT on close 207874 connections updated cached RTT variance on close 132439 connections updated cached ssthresh on close 42392 embryonic connections dropped 72339338 segments updated rtt (of 69477829 attempts) 390871 retransmit timeouts 0 connections dropped by rexmit timeout 0 persist timeouts 0 connections dropped by persist timeout 0 Connections (fin_wait_2) dropped because of timeout 13990 keepalive timeouts 2 keepalive probes sent 13988 connections dropped by keepalive 173044 correct ACK header predictions 36947371 correct data packet header predictions 1323420 syncache entries added 0 retransmitted 0 dupsyn 0 dropped 1323420 completed 0 bucket overflow 0 cache overflow 0 reset 0 stale 0 aborted 0 badack 0 unreach 0 zone failures 1323420 cookies sent 0 cookies received 1864 SACK recovery episodes 18005 segment rexmits in SACK recovery episodes 26066896 byte rexmits in SACK recovery episodes 147327 SACK options (SACK blocks) received 87473 SACK options (SACK blocks) sent 0 SACK scoreboard overflow 0 packets with ECN CE bit set 0 packets with ECN ECT(0) bit set 0 packets with ECN ECT(1) bit set 0 successful ECN handshakes 0 times ECN reduced the congestion window udp: 5141258 datagrams received 0 with incomplete header 0 with bad data length field 0 with bad checksum 1 with no checksum 0 dropped due to no socket 129616 broadcast/multicast datagrams undelivered 0 dropped due to full socket buffers 0 not for hashed pcb 5011642 delivered 5016050 datagrams output 0 times multicast source filter matched sctp: 0 input packets 0 datagrams 0 packets that had data 0 input SACK chunks 0 input DATA chunks 0 duplicate DATA chunks 0 input HB chunks 0 HB-ACK chunks 0 input ECNE chunks 0 input AUTH chunks 0 chunks missing AUTH 0 invalid HMAC ids received 0 invalid secret ids received 0 auth failed 0 fast path receives all one chunk 0 fast path multi-part data 0 output packets 0 output SACKs 0 output DATA chunks 0 retransmitted DATA chunks 0 fast retransmitted DATA chunks 0 FR's that happened more than once to same chunk 0 intput HB chunks 0 output ECNE chunks 0 output AUTH chunks 0 ip_output error counter Packet drop statistics: 0 from middle box 0 from end host 0 with data 0 non-data, non-endhost 0 non-endhost, bandwidth rep only 0 not enough for chunk header 0 not enough data to confirm 0 where process_chunk_drop said break 0 failed to find TSN 0 attempt reverse TSN lookup 0 e-host confirms zero-rwnd 0 midbox confirms no space 0 data did not match TSN 0 TSN's marked for Fast Retran Timeouts: 0 iterator timers fired 0 T3 data time outs 0 window probe (T3) timers fired 0 INIT timers fired 0 sack timers fired 0 shutdown timers fired 0 heartbeat timers fired 0 a cookie timeout fired 0 an endpoint changed its cookiesecret 0 PMTU timers fired 0 shutdown ack timers fired 0 shutdown guard timers fired 0 stream reset timers fired 0 early FR timers fired 0 an asconf timer fired 0 auto close timer fired 0 asoc free timers expired 0 inp free timers expired 0 packet shorter than header 0 checksum error 0 no endpoint for port 0 bad v-tag 0 bad SID 0 no memory 0 number of multiple FR in a RTT window 0 RFC813 allowed sending 0 RFC813 does not allow sending 0 times max burst prohibited sending 0 look ahead tells us no memory in interface 0 numbers of window probes sent 0 times an output error to clamp down on next user send 0 times sctp_senderrors were caused from a user 0 number of in data drops due to chunk limit reached 0 number of in data drops due to rwnd limit reached 0 times a ECN reduced the cwnd 0 used express lookup via vtag 0 collision in express lookup 0 times the sender ran dry of user data on primary 0 same for above 0 sacks the slow way 0 window update only sacks sent 0 sends with sinfo_flags !=0 0 unordered sends 0 sends with EOF flag set 0 sends with ABORT flag set 0 times protocol drain called 0 times we did a protocol drain 0 times recv was called with peek 0 cached chunks used 0 cached stream oq's used 0 unread messages abandonded by close 0 send burst avoidance, already max burst inflight to net 0 send cwnd full avoidance, already max burst inflight to net 0 number of map array over-runs via fwd-tsn's ip: 137814085 total packets received 0 bad header checksums 0 with size smaller than minimum 0 with data size < data length 0 with ip length > max ip packet size 0 with header length < data size 0 with data length < header length 0 with bad options 0 with incorrect version number 1200 fragments received 0 fragments dropped (dup or out of space) 0 fragments dropped after timeout 300 packets reassembled ok 137813009 packets for this host 530 packets for unknown/unsupported protocol 0 packets forwarded (0 packets fast forwarded) 61 packets not forwardable 0 packets received for unknown multicast group 0 redirects sent 137234598 packets sent from this host 0 packets sent with fabricated ip header 685307 output packets dropped due to no bufs, etc. 52 output packets discarded due to no route 300 output datagrams fragmented 1200 fragments created 0 datagrams that can't be fragmented 0 tunneling packets that can't find gif 0 datagrams with bad address in header icmp: 0 calls to icmp_error 0 errors not generated in response to an icmp message Output histogram: echo reply: 305 0 messages with bad code fields 0 messages less than the minimum length 0 messages with bad checksum 0 messages with bad length 0 multicast echo requests ignored 0 multicast timestamp requests ignored Input histogram: destination unreachable: 530 echo: 305 305 message responses generated 0 invalid return addresses 0 no return routes ICMP address mask responses are disabled igmp: 0 messages received 0 messages received with too few bytes 0 messages received with wrong TTL 0 messages received with bad checksum 0 V1/V2 membership queries received 0 V3 membership queries received 0 membership queries received with invalid field(s) 0 general queries received 0 group queries received 0 group-source queries received 0 group-source queries dropped 0 membership reports received 0 membership reports received with invalid field(s) 0 membership reports received for groups to which we belong 0 V3 reports received without Router Alert 0 membership reports sent arp: 376748 ARP requests sent 3207 ARP replies sent 245245 ARP requests received 80845 ARP replies received 326090 ARP packets received 267712 total packets dropped due to no ARP entry 108876 ARP entrys timed out 0 Duplicate IPs seen ip6: 2226633 total packets received 0 with size smaller than minimum 0 with data size < data length 0 with bad options 0 with incorrect version number 0 fragments received 0 fragments dropped (dup or out of space) 0 fragments dropped after timeout 0 fragments that exceeded limit 0 packets reassembled ok 2226633 packets for this host 0 packets forwarded 0 packets not forwardable 0 redirects sent 2226633 packets sent from this host 0 packets sent with fabricated ip header 0 output packets dropped due to no bufs, etc. 8 output packets discarded due to no route 0 output datagrams fragmented 0 fragments created 0 datagrams that can't be fragmented 0 packets that violated scope rules 0 multicast packets which we don't join Input histogram: UDP: 2226633 Mbuf statistics: 962679 one mbuf 1263954 one ext mbuf 0 two or more ext mbuf 0 packets whose headers are not continuous 0 tunneling packets that can't find gif 0 packets discarded because of too many headers 0 failures of source address selection Source addresses selection rule applied: icmp6: 0 calls to icmp6_error 0 errors not generated in response to an icmp6 message 0 errors not generated because of rate limitation 0 messages with bad code fields 0 messages < minimum length 0 bad checksums 0 messages with bad length Histogram of error messages to be generated: 0 no route 0 administratively prohibited 0 beyond scope 0 address unreachable 0 port unreachable 0 packet too big 0 time exceed transit 0 time exceed reassembly 0 erroneous header field 0 unrecognized next header 0 unrecognized option 0 redirect 0 unknown 0 message responses generated 0 messages with too many ND options 0 messages with bad ND options 0 bad neighbor solicitation messages 0 bad neighbor advertisement messages 0 bad router solicitation messages 0 bad router advertisement messages 0 bad redirect messages 0 path MTU changes rip6: 0 messages received 0 checksum calculations on inbound 0 messages with bad checksum 0 messages dropped due to no socket 0 multicast messages dropped due to no socket 0 messages dropped due to full socket buffers 0 delivered 0 datagrams output netstat -m 516/5124/5640 mbufs in use (current/cache/total) 512/1634/2146/32768 mbuf clusters in use (current/cache/total/max) 512/1536 mbuf+clusters out of packet secondary zone in use (current/cache) 0/1303/1303/12800 4k (page size) jumbo clusters in use (current/cache/total/max) 0/0/0/6400 9k jumbo clusters in use (current/cache/total/max) 0/0/0/3200 16k jumbo clusters in use (current/cache/total/max) 1153K/9761K/10914K bytes allocated to network (current/cache/total) 0/0/0 requests for mbufs denied (mbufs/clusters/mbuf+clusters) 0/0/0 requests for jumbo clusters denied (4k/9k/16k) 0/8/6656 sfbufs in use (current/peak/max) 0 requests for sfbufs denied 0 requests for sfbufs delayed 0 requests for I/O initiated by sendfile 0 calls to protocol drain routines Anyone got an idea what might be the possible cause?

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• `:Zone.Identifier` files keep on appearing in Windows XP virtual machine

  - by Jonathan Reno

  I have a Windows XP Home Edition guest and a Linux Mint 13 host. I use VirtualBox and the ~/Public directory is shared with the guest. It sometimes happens that I use IE on the guest system to download files (until I get a better Windows browser). All of the downloaded files go the the L:\ drive (the ~/Public directory). When they are finished downloading, Windows Explorer adds a :Zone.Identifier file for each file I download. When I extract a downloaded ZIP archive on the guest (on drive L:\), Windows creates a :Zone.Identifier file for every file in the extracted directory. This even occurs if I use the host to move a file to the ~/Public directory. The shared ~/Public directory is on an ext4 partition and the colon character is supposed to be illegal in file names in Windows, but not on the ext4 partition. Is there any way to stop Windows from putting all this rubbish on my filesystem? (I might have to create a shell script to clean up after Windows' act.) Here is what I see in Windows Explorer: By the way, if I were running a Mac OS X host (where colons are illegal file name characters) this would be even more horrendous.

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• Exchange 2010 Hub cannot deliver to Exchange 2007 Hub - "451 5.7.3 Cannot achieve Exchange Server authentication"

  - by Graeme Donaldson

  We have an existing Exchange 2007 server in Site A (exch07). I've installed an Exchange 2010 server in Site B (exch10). Both servers have the CAS, Mailbox and Hub roles. Messages sent via SMTP on exch10 which are destined for mailboxes on exch07 are queued with the "Last Error" reported in Queue Viewer as '451 4.4.0 Primary target IP address responded with: "451 5.7.3 Cannot achieve Exchange Server authentication." Attempted failover to alternate host, but that did not succeed. Either there are no alternate hosts, or delivery failed to all alternate hosts.' I've found that some people have resolved this by creating new Receive Connectors which are scoped specifically to apply to connections from the remote hub/s, but I have had no luck doing this. Specifically I created new receive connectors on both servers with the following settings: Remote IP = IP/s of remote server Authentication = "Transport Layer Security (TLS)" and "Exchange Server authentication" Permission Groups = "Exchange servers" and "Legacy Exchange Servers" This made no difference, I see the same error message. What am I missing? Update: We noticed that the Application log had this error message from MSExchangeTransportService: Microsoft Exchange could not find a certificate that contains the domain name exch07.domain.local in the personal store on the local computer. Therefore, it is unable to support the STARTTLS SMTP verb for the connector exch10 with a FQDN parameter of exch07.domain.local. If the connector's FQDN is not specified, the computer's FQDN is used. Verify the connector configuration and the installed certificates to make sure that there is a certificate with a domain name for that FQDN. If this certificate exists, run Enable-ExchangeCertificate -Services SMTP to make sure that the Microsoft Exchange Transport service has access to the certificate key. It turns out that the default self-signed certificate was no longer enabled for the SMTP service for some reason. After enabling the self-signed certificate for SMTP, we no longer get the error in the event logs, but delivery is still failing with the same error message. Update 2: I put a mailbox on exch10 and attempted to deliver a message via SMTP on exch07 and I get the same error.

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• Is it possible to trace the delegation path for a DNS lookup?

  - by Josh Glover

  I'm trying to determine why a Nagios host check is failing (hostnames and IPs have been changed to protect the guilty): : jmglov@laurana; host www.foo.com ;; connection timed out; no servers could be reached : jmglov@laurana; for ns in `grep -o '\([0-9]\+[.]\)\{3\}[0-9]\+$' /etc/resolv.conf`; do ping -qc 1 $ns; done PING 192.168.1.1 (192.168.1.1) 56(84) bytes of data. --- 192.168.1.1 ping statistics --- 1 packets transmitted, 1 received, 0% packet loss, time 0ms rtt min/avg/max/mdev = 10.911/10.911/10.911/0.000 ms PING 192.168.1.2 (192.168.1.2) 56(84) bytes of data. --- 192.168.1.2 ping statistics --- 1 packets transmitted, 1 received, 0% packet loss, time 0ms rtt min/avg/max/mdev = 0.241/0.241/0.241/0.000 ms So I know that my nameservers are reachable, meaning that some nameserver along the delegation path to the authoritative nameserver for my host is not responding. Is there an easy way to determine which nameserver this is (basically a traceroute for DNS)?

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• Debian: Should I add vlan interface into bridge for KVM?

  - by javano

  I am setting up a Debian Squeeze box as a KVM host. I want to add multiple interfaces to each KVM guest so I want them to be on different VLANs. After reading about this, I believe the best method is to add multiple logical VLAN (sub)-interfaces to the physical NICs and then create a bridge adapter for each VLAN interace, and assign each bridge as a NIC for KVM guests. Does this make good sense, or madness? Do I have to use bridged interfaces with KVM like this? Can't I just add eth1.xx and eth1.yy to my interfaces config below and then configure those directly as bridged KVM guest NICs? If so, how should this look in the interfaces config file below? user@host:~$ cat /etc/network/interfaces # This file describes the network interfaces available on your system # and how to activate them. For more information, see interfaces(5). # The loopback network interface auto lo iface lo inet loopback # Management Interface auto eth0 iface eth0 inet static address 172.22.0.31 netmask 255.255.255.0 gateway 172.22.0.1 # Interface for guest VMs auto eth1 # Guest1 : Use VLAN 117 auto eth1.117 iface eth1.117 inet manual # Set up br1 for guest 1, bridging with vlan 117 auto br1.117 iface br1.117 inet manual bridge_ports eth1.117 bridge_stp off user@host:~$ uname -a Linux hostname 3.4.9 #1 SMP Wed Aug 22 19:08:46 BST 2012 x86_64 GNU/Linux UPDATE I would really like it if someone could clarify the config for me, as I have also seen the above configured with this syntax, so I don't see why one would be preferred over the other; # Interface for guest VMs auto eth1 allow-hotplug eth1 iface eth1 inet static # Vlan 117 for guest 1 auto vlan 117 iface vlan111 inet static vlan_raw_device eth1 # Guest 1 : NIC 1 auto br1.117 iface br1.117 inet manual bridge_ports vlan117 bridge_stp off

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• Postfix not working

  - by user1488723

  A while ago I installed the postfix mail server on my ubuntu 10.04 VPS. At the time it was working good but now it's just stopped working. I was trying to enable SASL authentification and somewhere it must have went really wrong. I've studied the postfix main.cf and done everything in an orderly fashion to ensure that it is nothing wrong. I also have Dovecot installed and configured dovecot.conf to run with Postfix. If I try to do telnet localhost 25 while logged in on the server I just get: Connection closed by foreign host. If I try to do telnet mail.example.com 25 "from the outside" I get: telnet: Unable to connect to remote host: No route to host And when I check the server log after the failed attempts I see this: Jun 28 15:49:31 msv postfix/smtpd[11839]: initializing the server-side TLS engine Jun 28 15:49:31 msv postfix/smtpd[11839]: connect from localhost.localdomain[127.0.0.1] Jun 28 15:49:31 msv postfix/smtpd[11839]: warning: SASL: Connect to /var/spool/postfix/private/auth failed: Connection refused Jun 28 15:49:31 msv postfix/smtpd[11839]: fatal: no SASL authentication mechanisms Jun 28 15:49:32 msv postfix/master[11598]: warning: process /usr/lib/postfix/smtpd pid 11839 exit status 1 Jun 28 15:49:32 msv postfix/master[11598]: warning: /usr/lib/postfix/smtpd: bad command startup -- throttling main.cf file looks like this: smtpd_banner = $myhostname ESMTP $mail_name (Ubuntu) biff = no append_dot_mydomain = no delay_warning_time = 4h myhostname = mail.example.com alias_maps = hash:/etc/aliases alias_database = hash:/etc/aliases mydomain = example.com myorigin = $mydomain mydestination = $mydomain relayhost = mynetworks = 127.0.0.1 mailbox_command = procmail -a "$EXTENSION" mailbox_size_limit = 0 recipient_delimiter = + inet_interfaces = all smtpd_use_tls = yes smtpd_tls_loglevel = 2 smtpd_tls_cert_file = /etc/postfix/ssl/smtpd.crt smtpd_tls_key_file = /etc/postfix/ssl/smtpd.key smtpd_tls_CAfile = /etc/postfix/ssl/cacert.pem smtpd_sasl_auth_enable = yes smtpd_client_restrictions = permit_sasl_authenticated, permit_mynetworks, reject_unauth_destination smtpd_sender_restrictions = permit_sasl_authenticated, permit_mynetworks smtpd_recipient_restrictions = permit_sasl_authenticated, reject_unauth_destination broken_sasl_auth_clients = yes smtpd_sasl_type = dovecot smtpd_sasl_path = /var/spool/postfix/private/auth smtpd_sasl_security_options = noanonymous Dovecot.conf file looks like this: protocols = imap imaps disable_plaintext_auth = no log_timestamp = "%b %d %H:%M:%S " ssl = yes ssl_cert_file = /etc/postfix/ssl/smtpd.crt ssl_key_file = /etc/postfix/ssl/smtpd.key mail_location = maildir:~/mail mail_access_groups = mail auth_username_chars = abcdefghijklmnopqrstuvwxyz protocol imap { imap_client_workarounds = delay-newmail tb-extra-mailbox-sep } auth default { mechanisms = plain login passdb pam { } userdb passwd { } socket listen { client { path = /var/spool/postfix/private/auth user = postfix group = postfix mode = 0660 } } }

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• Cannot connect to Solaris Server when Oracle GoldenGate process uses the port

  - by Abdallah Ghrb

  I'm trying to test the Oracle goldengate to replicate data between two databases on the same server. So I installed two databases and two goldengate homes in the same machine. The goldengate processes are started from each home and they are responsible for the replication : Process from home 1 configured on port 7809 & process for home 2 configured on port 7810. For a successful replication, processes started from goldengate home 1 should communicate with processes started from goldengate home 2. But for some reasons, this is not happening. The goldengate log file has the following error : OGG-01223 Oracle GoldenGate Capture for Oracle, exthrr.prm: TCP/IP error 131 (Connection reset by peer). "Googling" for this error, it said that the connection occurred but the host terminated it. Tried to telnet the machine with the used port and it gave the following error: bash-3.00$ telnet 10.10.3.124 7810 Trying 10.10.3.124... Connected to 10.10.3.124. Escape character is '^]'. Connection to 10.10.3.124 closed by foreign host. Here the communication occurs but for only around 3 seconds then it is closed by the host, which is the same explanation of the above error in the goldengate log file. I tried to change the port but still the same error. The problem is happening only when the goldengate process is using the port. When other process is using the same port, I can telnet successfully.

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• How to bypass vpn talking to VMWare Guest?

  - by marc esher

  Greetings. Network/VPN n00b question here. I'm running VMWare Workstation with a Guest Windows 2003 Server. It has SQL Server 2000 installed. The sole purpose for this Guest is to house SQL Server... it needn't have internet access or access to any other resources on the network other than the host. When launch Check Point VPN software, the host routes through the company network before it connects to the guest ... i.e. it's no longer a direct connection. I assume this is just how things are supposed to work. However, what's happening is that the connection between my host and the SQL Server instance on the guest intermittently drops. It's not consistent, and some databases on the server will be responsive while others aren't. It appears that the databases with the most traffic on the guest (the ones I'm hitting with load tests) are the ones that become intermittently unresponsive. This problem only manifests when VPN is on; when it's off, I can pound away on this database with no troubles. Thanks for any advice!

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• ssh connection operation timed out using rsync

  - by Mark Molina

  I use rsync to backup my remote server on my local device but when I combine it with a cron job my ssh times out. Just to be clear, the data is stored on a remote server and I want it stored on my local server. The backup request must be sent from my local server to the remote server. The command for backup up the data is working when I just type it in terminal like this: rsync -chavzP --stats USERNAME@IPADDRES: PATH_TO_BACKUP LOCAL_PATH_TO_BACKUP but when I combine it with a cron job like this: 10 11 * * * rsync -chavzP --stats USERNAME@IP_ADDRESS: PATH_TO_BACKUP LOCAL_PATH_TO_BACKUP the ssh connection times out. When the cronjob executes it send a mail to the root user with the output like this: From local.xx.xx.xx Tue Jul 2 11:20:17 2013 X-Original-To: username Delivered-To: [email protected] From: [email protected] (Cron Daemon) To: [email protected] Subject: Cron <username@server> rsync -chavzP --stats USERNAME@IPADDRES: PATH_TO_BACKUP LOCAL_PATH_TO_BACKUP X-Cron-Env: <SHELL=/bin/sh> X-Cron-Env: <PATH=/usr/bin:/bin> X-Cron-Env: <LOGNAME=username> X-Cron-Env: <USER=username> X-Cron-Env: <HOME=/Users/username> Date: Tue, 2 Jul 2013 11:20:17 +0200 (CEST) ssh: connect to host IP_ADDRESS port XX: Operation timed out rsync: connection unexpectedly closed (0 bytes received so far) [receiver] rsync error: unexplained error (code 255) at /SourceCache/rsync/rsync-42/rsync/io.c(452) [receiver=2.6.9] So the rsync command is working when just typed in terminal but not when used by a cronjob. Can anybody explain this?

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• linux hardware raid 10 / lvm / virtual machine partition alignment and filesystem optimization

  - by Jason Ward

  I've been reading everything I can find about partition alignment and filesystem optimization (ext4 and xfs) but still don't know enough to be confident in setting up my current configuration. My remaining confusion comes from the LVM layer and if I should use raid parameters on the filesystem in guest os'es. My main questions are: When I use 'pvcreate --dataalignment' do I use the stripe-width as calculated for a filesystem on RAID (128kB for ext4 in my situation), the Stripe size of the RAID set (256kB), something else altogether, or do I not need this? When I create ext2/3/4 or xfs filesystems in guests on the Logical Volumes, should I add the settings for the underlying RAID (e.g. mkfs.ext4 -b 4096 -E stride=64,stripe-width=128)? Does anyone see any glaring errors in my set up below? I'm running some benchmarks now but haven't done enough to start comparing results. I have four drives in RAID 10 on a 3ware 9750-4i controller (more details on the settings below) giving me a 6.0TB device at /dev/sda. Here is my partition table: Model: LSI 9750-4i DISK (scsi) Disk /dev/sda: 5722024MiB Sector size (logical/physical): 512B/512B Partition Table: gpt Number Start End Size File system Name Flags 1 1.00MiB 257MiB 256MiB ext4 BOOTPART boot 2 257MiB 4353MiB 4096MiB linux-swap(v1) 3 4353MiB 266497MiB 262144MiB ext4 4 266497MiB 4460801MiB 4194304MiB Partition 1 is to be the /boot partition for my xen host. Partition 2 is swap. Partition 3 is to be the root (/) for my xen host. Partition 4 is to be (the only) physical volume to be used by LVM (for those who are counting, I left about 1.2TB unallocated for now) For my Xen guests, I usually create a Logical Volume of the needed size and present it to the guests for them to partition as needed. I know there are other ways of handling that but this method works best for my situation. Here's the hardware of interest on my CentOS 6.3 Xen Host: 4x Seagate Barracuda 3TB ST3000DM001 Drives (sector size: 512 logical/4096 physical) 3ware 9750-4i w/BBU (sector size reported: 512 logical/512 physical) All four drives make up a RAID 10 array. Stripe: 256kB Write Cache enabled Read Cache: intelligent StoreSave: Balance Thanks!

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