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• I want to change DPI with Imagemagick without changing the actual byte-size of the image data

  - by user1694803

  I feel so horribly sorry that I have to ask this question here, but after hours of researching how to do an actually very simple task I'm still failing... In Gimp there is a very simple way to do what I want. I only have the German dialog installed but I'll try to translate it. I'm talking about going to "Picture-PrintingSize" and then adjusting the Values "X-Resolution" and "Y-Resolution" which are known to me as so called DPI values. You can also choose the format which by default is "Pixel/Inch". (In German the dialog is "Bild-Druckgröße" and there "X-Auflösung" and "Y-Auflösung") Ok, the values there are often "72" by default. When I change them to e.g. "300" this has the effect that the image stays the same on the computer, but if I print it, it will be smaller if you look at it, but all the details are still there, just smaller - it has a higher resolution on the printed paper (but smaller size... which is fine for me). I am often doing that when I am working with LaTeX, or to be exact with the command "pdflatex" on a recent Ubuntu-Machine. When I'm doing the above process with Gimp manually everything works just fine. The images will appear smaller in the resulting PDF but with high printing quality. What I am trying to do is to automate the process of going into Gimp and adjusting the DPI values. Since Imagemagick is known to be superb and I used it for many other tasks I tried to achieve my goal with this tool. But it does just not do what I want. After trying a lot of things I think this actually is be the command that should be my friend: convert input.png -density 300 output.png This should set the DPI to 300, as I can read everywhere in the web. It seems to work. When I check the file it stays the same. file input.png output.png input.png: PNG image data, 611 x 453, 8-bit grayscale, non-interlaced output.png: PNG image data, 611 x 453, 8-bit grayscale, non-interlaced When I use this command, it seems like it did what I wanted: identify -verbose output.png | grep 300 Resolution: 300x300 PNG:pHYs : x_res=300, y_res=300, units=0 (Funny enough, the same output comes for input.png which confuses me... so this might be the wrong parameters to watch?) But when I now render my TeX with "pdflatex" the image is still big and blurry. Also when I open the image with Gimp again the DPI values are set to "72" instead of "300". So there actually was no effect at all. Now what is the problem here. Am I getting something completely wrong? I can't be that wrong since everything works just fine with Gimp... Thanks for any help in this. I am also open to other automated solutions which are easily done on a Linux system...

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• SQL Server Issue: Could not allocate space for object ... primary filegroup is full

  - by Luke

  Trying to figure out a problem at an office that has SQL Server 2005 installed on Windows SBS Server 2008. Here's the setup: It's an office, and the person who set this all up is nowhere to be found. I'm the best hope they have... One of the programs they use on a workstation gives them an error of "Could not allocate space for object 'Billing' in database "MyDatabase" because primary filegroup is full" when trying to save an entry in their software. I searched around for hours, looking for possible solutions. One was to check for available disk space, and another was to defrag. I checked the hard drives on the server, and there is plenty of space free. I also defragged, which may have helped the problem somewhat. It's hard to say, because it seems like with the nature of the error, if you try over and over you might get it to actually save. My next step was to try to see if autogrowth was enabled on the database. This would seem to be a likely / possible solution, but I can't access the database! If I run the SQL Management Studio, I can log in as my Windows user and view the list of databases. However, if I try to do anything (actually view the database, view the properties, add or edit users), I get errors that I don't have permission. For what it's worth, I also tried runing Management Studio as Administrator, in case that would help. No difference, though. Now, what I'm guessing is going on -- from my limited knowledge of SQL and from reading online -- is that though I'm logged in as a Windows administrator, that account does NOT have SQL access. I do see a list of SQL users, including SA, but I again don't have permission to add one or to change the password on an existing one. And nobody at the office has any idea what the SQL passwords could be. So... here's my thinking thus far: 1 - The "Could not allocate" error likely points to a database that needs to be allowed to autogrow. Especially since I verified there is plenty of free space and the HD has been defragmented. 2 - Enabling autogrow would be very easy to do if I had the proper access within SQL Management Stuido. That leads me to this link: http://blogs.technet.com/b/sqlman/archive/2011/06/14/tips-amp-tricks-you-have-lost-access-to-sql-server-now-what.aspx It sounds like it's a step-by-step guide for giving me the access I need to SQL. I'm guessing that if I followed this guide, I would be able to then log in to the SQL server via Management Studio with the proper permissions, and would be able to enable autogrow (or simply view the status of the existing database), and hopefully solve the "Could not allocate space" problem! So I guess I have a few questions: 1 - Would you guys agree with my "diagnosis"? Think I'm barking up the right tree? 2 - Is there any risk at all in hurting / disabling / wrecking the current SQL database or setup with me going through the guide to regain SQL access? I understand that per the guide, I would have to temporarily shut down SQL, so obviously it wouldn't be accessible during that time. But it wouldn't be worth the risk if there's a chance I could mess anything up... Like I said, the workstations ARE currently accessing the database somehow, but nobody knows with what login info or anything. Basically, it's set up, it works (usually), but if they had to reload the software, nobody would know how. Any feedback would be appreciated!! The problem is such that it's not an emergency for them, but an annoyance. If I could fix it, it would be wonderful. But if not, I think they'll manage, especially as they are going to eventually stop using this software. Thank you so much for your time! Luke

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• Prevent auto mounting Android sdcard under Linux Mint

  - by BullShark

  I recently obtained an older Android phone, so that I could test Android Apps on it. I've needed it because I have a Nexus 7 but not older Android versions, hardware, etc. to test on. I'm having a problem with it under Linux Mint with Cinnamon. When I plug the phone in, or remove and plug the sdcard from the phone back to it while the phone is plugged in, Linux automatically mounts the sdcard. This is a problem because once it is mounted under Linux, it dismounts from the phone running Android 2.3.5, and I can no longer test Android Apps I write that require the sdcard to be present, writable. I went to Menu System Tools System Settings System Details Removable Media, and it brings up this window. I have changed the settings to always "Ask what to do" on "Select how media should be handled". However, the sdcard still gets mounted and then I am asked how I want to open these files (media players, photo importers, file browser, etc.). If I click the checkbox for "Never prompt or start programs on media insertion", then the sdcard is mounted, and I am not asked how to open these files. Eject is just a noob word for Ubuntu users that means umount (unmount) like "Adminstrator" is another ubuntu noob word for the root user. And if I unmount the sdcard, the phone doesn't recognize it again until I take the sdcard out and plug it back in. The phone sees it for a brief moment until Linux Mint takes it over. There are 2 possible solutions and maybe more: 1) Prevent Linux from automounting sdcards some how 2) Tell Android not to allow the computer it is plugged into to take over the sdcard, HOW? Edit: I found out how to prevent the sdcard from being automatically mounted: Now it gets recognized by Linux: bullshark@beastlinux ~ $ dmesg | tail -n 25 [597212.218323] sd 21:0:0:0: [sde] Attached SCSI removable disk [597212.218639] sr 21:0:0:1: Attached scsi CD-ROM sr2 [597212.218910] sr 21:0:0:1: Attached scsi generic sg7 type 5 [597217.139373] sd 21:0:0:0: [sde] 3862528 512-byte logical blocks: (1.97 GB/1.84 GiB) [597217.140726] sd 21:0:0:0: [sde] No Caching mode page present [597217.140735] sd 21:0:0:0: [sde] Assuming drive cache: write through [597217.143595] sd 21:0:0:0: [sde] No Caching mode page present [597217.143602] sd 21:0:0:0: [sde] Assuming drive cache: write through [597217.152240] sde: sde1 [597389.751008] 4:2:1: cannot get freq at ep 0x84 [597390.238742] 4:2:1: cannot get freq at ep 0x84 [597624.903132] sde: detected capacity change from 1977614336 to 0 [597637.677763] sd 21:0:0:0: [sde] 3862528 512-byte logical blocks: (1.97 GB/1.84 GiB) [597637.679616] sd 21:0:0:0: [sde] No Caching mode page present [597637.679626] sd 21:0:0:0: [sde] Assuming drive cache: write through [597637.682508] sd 21:0:0:0: [sde] No Caching mode page present [597637.682515] sd 21:0:0:0: [sde] Assuming drive cache: write through [597637.692758] sde: sde1 [597661.857979] sde: detected capacity change from 1977614336 to 0 [597688.775455] sd 21:0:0:0: [sde] 3862528 512-byte logical blocks: (1.97 GB/1.84 GiB) [597688.776814] sd 21:0:0:0: [sde] No Caching mode page present [597688.776823] sd 21:0:0:0: [sde] Assuming drive cache: write through [597688.780055] sd 21:0:0:0: [sde] No Caching mode page present [597688.780062] sd 21:0:0:0: [sde] Assuming drive cache: write through [597688.788639] sde: sde1 bullshark@beastlinux ~ $ However, the phone still unmounts the sdcard upon being detected by Linux. Linux detects but does not mount, and a few seconds later: Edit #2 (Solution): I solved this one by changing the usb connection type (was usb mass storage) :

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• Unable to Mange DNS via MMC

  - by IT Helpdesk Team Manager

  When trying to access the DNS service on Microsoft Windows Server 2003 (Build 3790) domain controller/schema master via the MMC DNS snap in or locally via the DNS MMC from Administrative tools I'm getting a red "X" through the icon for the DNS Server. The inability to access DNS management via MMC happens on all domain controllers as well. We've looked at items such as the DHCP client not being started, incorrect DNS setup ( the machine points at itself and another DC ), the DNS service not running ( it is and all DNS queries via NSLOOKUP work correctly ), dslint returns the correct information and functions as expected. There is the following entry in the DNS event log: The DNS server could not initialize the remote procedure call (RPC) service. If it is not running, start the RPC service or reboot the computer. The event data is the error code. For more information, see Help and Support Center at http://go.microsoft.com/fwlink/events.asp. 0000: 0000051b dnscmd fails with RPC server unavailable yet RPC is started: C:\Documents and Settings\Administrator.DOMAIN>dnscmd /Info Info query failed status = 1722 (0x000006ba) Command failed: RPC_S_SERVER_UNAVAILABLE 1722 (000006ba) DCDIAG /TEST:DNS /V /E produces the following errors: Warning: no DNS RPC connectivity (error or non Microsoft DNS server is running) [Error details: 1753 (Type: Win32 - Description: There are no more endpoints available from the endpoint mapper.)] Warning: no DNS RPC connectivity (error or non Microsoft DNS server is running) [Error details: 1722 (Type: Win32 - Description: The RPC server is unavailable.)] The DNS server could not initialize the remote procedure call (RPC) service. If it is not running, start the RPC service or reboot the computer. The event data is the error code. A DNS query for _ldap._tcp.dc._msdcs. returns the correct results. All domain and ADS related activities are working except that I can't manage my DNS via MMC or dnscmd. Any thoughts or solutions would be greatly appreciated. EDIT: Adding Registry export per request: Key Name: HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Rpc Class Name: <NO CLASS> Last Write Time: 10/18/2012 - 2:29 PM Value 0 Name: DCOM Protocols Type: REG_MULTI_SZ Data: ncacn_ip_tcp Value 1 Name: UuidSequenceNumber Type: REG_DWORD Data: 0xb19bd0f Key Name: HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Rpc\ClientProtocols Class Name: <NO CLASS> Last Write Time: 3/9/2007 - 12:11 PM Value 0 Name: ncacn_np Type: REG_SZ Data: rpcrt4.dll Value 1 Name: ncacn_ip_tcp Type: REG_SZ Data: rpcrt4.dll Value 2 Name: ncadg_ip_udp Type: REG_SZ Data: rpcrt4.dll Value 3 Name: ncacn_http Type: REG_SZ Data: rpcrt4.dll Value 4 Name: ncacn_at_dsp Type: REG_SZ Data: rpcrt4.dll Key Name: HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Rpc\NameService Class Name: <NO CLASS> Last Write Time: 2/20/2006 - 4:48 PM Value 0 Name: DefaultSyntax Type: REG_SZ Data: 3 Value 1 Name: Endpoint Type: REG_SZ Data: \pipe\locator Value 2 Name: NetworkAddress Type: REG_SZ Data: \\. Value 3 Name: Protocol Type: REG_SZ Data: ncacn_np Value 4 Name: ServerNetworkAddress Type: REG_SZ Data: \\. Key Name: HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Rpc\NetBios Class Name: <NO CLASS> Last Write Time: 2/20/2006 - 4:48 PM Key Name: HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Rpc\RpcProxy Class Name: <NO CLASS> Last Write Time: 3/9/2007 - 12:11 PM Value 0 Name: Enabled Type: REG_DWORD Data: 0x1 Value 1 Name: ValidPorts Type: REG_SZ Data: pdc:100-5000 Key Name: HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Rpc\SecurityService Class Name: <NO CLASS> Last Write Time: 2/20/2006 - 4:48 PM Value 0 Name: 9 Type: REG_SZ Data: secur32.dll Value 1 Name: 10 Type: REG_SZ Data: secur32.dll Value 2 Name: 14 Type: REG_SZ Data: schannel.dll Value 3 Name: 16 Type: REG_SZ Data: secur32.dll Value 4 Name: 1 Type: REG_SZ Data: secur32.dll Value 5 Name: 18 Type: REG_SZ Data: secur32.dll Value 6 Name: 68 Type: REG_SZ Data: netlogon.dll

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• Random Slow Response

  - by ARehman

  We have an ASP.NET MVC 1.0 application running on Windows Server 2008 – Standard (32 –bit), Dual Core Xeon (3.0 GHz), 2 G.B R.A.M. Most of the times application renders response in 3-4 seconds, but sometimes users get very late response and delay is up to 40 seconds or more than a minute. It happens in following way: User browsed a page, idle for 5, 10 or 15 minutes, tried to browse same page or some other. Now, there is a chance that he will see late response whereas the app pool is still up and running. This can happen with any arbitrary page. We have tried followings/observations. Moved the application to stand alone web server App Pool idle shutdown time is 60 minutes. There are no abrupt shut downs/restarts. CPU or memory doesn’t spike. No delays in SQL queries. Modified App Pool setting to run in classic-mode. It didn’t help. Plugged-in custom module to log all those requests which took more than 5 seconds to complete. It didn’t pick any request of interest. Enabled ‘Failed Request Tracing’ to log all those requests which take 20 or more seconds to complete. It didn’t log anything. Event Viewer, HTTPER log, W3SVC logs or WAS logs don’t indicate anything. HTTPERR only has ‘_ _ Timer_ConnectionIdle _ _’ entries. There is not much traffic to server. This can happen also if only two users are active. Next we captured TCP/IP terrific on both a user and server end with Wireshark and below are details in brief of this slowness: Browser sends a request for ~/User/Home/ (GET Request) by setting up a receiving end point using port 'wlbs(port-2504)'. I'm not sure if this could be a problem in some way that browser didn't hand-shake with the server first and assumed that last connection is still open, whereas, I browsed the same page 4 minutes ago and didn't perform any activity with site after that. If I see the HTTPERR log, it indicates that it has ‘_ _ Timer_ConnectionIdle _ _ _’ entry for my last activity with server. Browser (I was using Chrome) waits for any response from the server, doesn’t find any then starts retransmitting the same request using same end point after incrementing wait intervals, e.g. after 8, 18, 29, 40, 62, and 92 seconds. All these GET requests were received by server as well. But, server didn’t send any packet to client. Browser didn't see any response on the end point it set up in point 1, it opened a new end point 'optiwave-lm (port-2524)', did a hand shake with the server and transmitted the same request again. Server received, processed it, and returned successful response. What happened to earlier 6-7 requests? Whether they were passed on to HTTP.SYS or not? Why Failed Request Tracing not logged anything, we didn't find any clue yet. Server served the same page successfully just 4 minutes ago. Looking forward for more suggestions/solutions. -- Thanks

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• Failed Administrator login on WSO2 IS with external OpenLDAP

  - by Marco Rivadeneyra

  I have an installation of WSO2 Identity Server and I'm trying to make it work with an external OpenLDAP instance I have followed this guide: http://wso2.org/project/solutions/identity/3.2.3/docs/user-core/admin_guide.html#LDAP For the read-only mode. But when I try to log-in I get a failed login and the following error on the console: TID: [0] [WSO2 Identity Server] [2012-08-10 17:10:25,493] WARN {org.wso2.carbon.core.services.util.CarbonAuthenticationUtil} - Failed Administrator login attempt 'john[0]' at [2012-08-10 17:10:25,0493] from IP address 127.0.0.1 {org.wso2.carbon.core.services.util.CarbonAuthenticationUtil} Full log: http://pastebin.com/pHUGXBqv My configuration file looks as follows: <UserManager> <Realm> <Configuration> <AdminRole>admin</AdminRole> <AdminUser> <UserName>john</UserName> <Password>johnldap</Password> </AdminUser> <EveryOneRoleName>everyone</EveryOneRoleName> <!-- By default users in this role sees the registry root --> <ReadOnly>true</ReadOnly> <MaxUserNameListLength>500</MaxUserNameListLength> <Property name="url">jdbc:h2:repository/database/WSO2CARBON_DB</Property> <Property name="userName">wso2carbon</Property> <Property name="password">wso2carbon</Property> <Property name="driverName">org.h2.Driver</Property> <Property name="maxActive">50</Property> <Property name="maxWait">60000</Property> <Property name="minIdle">5</Property> </Configuration> <UserStoreManager class="org.wso2.carbon.user.core.ldap.LDAPUserStoreManager"> <Property name="ReadOnly">true</Property> <Property name="MaxUserNameListLength">100</Property> <Property name="ConnectionURL">ldap://192.168.81.144:389</Property> <Property name="ConnectionName">cn=admin,dc=example,dc=com</Property> <Property name="ConnectionPassword">admin</Property> <Property name="UserSearchBase">ou=People,dc=example,dc=com</Property> <Property name="UserNameListFilter">(objectClass=inetOrgPerson)</Property> <Property name="UserNameAttribute">uid</Property> <Property name="ReadLDAPGroups">false</Property> <Property name="GroupSearchBase">ou=Groups,dc=example,dc=com</Property> <Property name="GroupSearchFilter">(objectClass=groupOfNames)</Property> <Property name="GroupNameAttribute">uid</Property> <Property name="MembershipAttribute">member</Property> </UserStoreManager> <AuthorizationManager class="org.wso2.carbon.user.core.authorization.JDBCAuthorizationManager"></AuthorizationManager> </Realm> I followed this guide to configure my LDAP server up to Loggging: https://help.ubuntu.com/12.04/serverguide/openldap-server.html Could you suggest what might be wrong? The LDAP log is available at: http://pastebin.com/T9rFYEAW

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• How to set up a centralized backup server with lots of offsite workstations, intermittent internet connectivity, and stubborn users?

  - by Zac B

  This might be an impossible question. Context: We have a bunch of computers across around 1000 users. We have a centralized office where 900 of the users work, most of the time. Most of the computers are laptops. They are very frequently coming on and off the network for hours at a time. Users often take their computers home and do lots of work from home. In addition, there are a handful of users who work elsewhere in the country, who are offline (no internet connection whatsoever) for more than half of the time they use their machines. All of the machines are Windows 7/XP. Problem: People are always losing data. One day someone accidentally deletes a bunch of files. The next day someone else installs a bad driver or tries to mess with something in system32 and needs a personal data backup/reinstall of Windows. Because of how many of our business operations are done without an internet connection, and how frequently computers come on- and offline, it's unfeasible to make users use network storage for all of their data. We tried giving them Dropboxes, and they stored their files elsewhere. We bought and deployed Altiris, and they uninstalled it and blamed us when they couldn't get files back that they accidentally deleted while they were offline and hadn't taken a backup in months. We tried teaching them backup best-practices, and using scheduled sync tools to upload things to the network drives, and they turned them off because they "looked like viruses". It doesn't help that many of these users are pretty high up in the business and are not amicable to any sort of "you need to do something regularly because we say so" solution. Question: Other than finding another job where IT is treated differently and users are willing to follow best practices, how would people recommend I implement a file backup solution that supports the following: Backs up to a centralized server over LAN or WAN whenever a network link becomes available, or on a schedule. Supports interrupted/resumed backups (and hopefully file-delta only backups), since connections to the network (WAN or LAN) are often slow and only open for half an hour or so. Supports relatively rapid, "I accidentally deleted the TPS reports! Oh no!" single-file recovery, ideally administered from the central backup server rather than the client PC. Supports local-to-local file delta backup on a schedule, so that users without a network connection for a few days can still retrieve accidental deletions or whatnot. Ideally, the local stored backups would be pushed up to the server whenever network link is available. Isn't configurable on the clients without certain credentials. Because the CFOs (who won't give up their admin rights on the domain) will disable it if they can. Backs up the entire hard drive. There are people who are self-righteous about storing things in C:\, or in the recycle bin, or in the C:\Windows dir (yes, I know). I'm fine integrating multiple products/solutions, or scripting different programs together myself (I'm a somewhat competent programmer), but I've been drawing a blank on where to start. Dropbox is folder-specific, Altiris doesn't cope with LAN outages or interrupted/resumed backups, Volume Shadow Copy is awesome for a local-to-local solution, but I don't know how to push days of stored shadow copies up to a server in a 2 hour window of network access. The company is fine with spending decent money on this, thousands (USD) on a server, and hundreds on clients, if necessary. I want to emphasize that this isn't a shopping list request. While I wish there was a program out there that did what I want, I've looked pretty hard, and not found anything that fits the bill. Instead, I'm hoping for ideas on where to start hacking things together from scratch/from different technologies to make something stable that works. Cheers!

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• Expert iptables help needed?

  - by Asad Moeen

  After a detailed analysis, I collected these details. I am under a UDP Flood which is more of application dependent. I run a Game-Server and an attacker is flooding me with "getstatus" query which makes the GameServer respond by making the replies to the query which cause output to the attacker's IP as high as 30mb/s and server lag. Here are the packet details, Packet starts with 4 bytes 0xff and then getstatus. Theoretically, the packet is like "\xff\xff\xff\xffgetstatus " Now that I've tried a lot of iptables variations like state and rate-limiting along side but those didn't work. Rate Limit works good but only when the Server is not started. As soon as the server starts, no iptables rule seems to block it. Anyone else got more solutions? someone asked me to contact the provider and get it done at the Network/Router but that looks very odd and I believe they might not do it since that would also affect other clients. Responding to all those answers, I'd say: Firstly, its a VPS so they can't do it for me. Secondly, I don't care if something is coming in but since its application generated so there has to be a OS level solution to block the outgoing packets. At least the outgoing ones must be stopped. Secondly, its not Ddos since just 400kb/s input generates 30mb/s output from my GameServer. That never happens in a D-dos. Asking the provider/hardware level solution should be used in that case but this one is different. And Yes, Banning his IP stops the flood of outgoing packets but he has many more IP-Addresses as he spoofs his original so I just need something to block him automatically. Even tried a lot of Firewalls but as you know they are just front-ends to iptables so if something doesn't work on iptables, what would the firewalls do? These were the rules I tried, iptables -A INPUT -p udp -m state --state NEW -m recent --set --name DDOS --rsource iptables -A INPUT -p udp -m state --state NEW -m recent --update --seconds 1 --hitcount 5 --name DDOS --rsource -j DROP It works for the attacks on un-used ports but when the server is listening and responding to the incoming queries by the attacker, it never works. Okay Tom.H, your rules were working when I modified them somehow like this: iptables -A INPUT -p udp -m length --length 1:1024 -m recent --set --name XXXX --rsource iptables -A INPUT -p udp -m string --string "xxxxxxxxxx" --algo bm --to 65535 -m recent --update --seconds 1 --hitcount 15 --name XXXX --rsource -j DROP They worked for about 3 days very good where the string "xxxxxxxxx" would be rate-limited, blocked if someone flooded and also didn't affect the clients. But just today, I tried updating the chain to try to remove a previously blocked IP so for that I had to flush the chain and restore this rule ( iptables -X and iptables -F ), some clients were already connected to servers including me. So restoring the rules now would also block some of the clients string completely while some are not affected. So does this mean I need to restart the server or why else would this happen because the last time the rules were working, there was no one connected?

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• Cheapest way to connect 20-24 Sata II HDDs in a budget storage server?

  - by Joe Hopfgartner

  I need to assemble a high density storage server for as cheap as possible. It's been a while for me and the last systems I integrated didn't even have Sata yet... During my Research I of course stumbled about Nexsan SATA Beast, the BackBlaze storage Pods as well as some ridiculously overpriced HP Proliant or Dell storage solutions. Finally I choose Norco cases as the way to go. My eye is set on the RPC-4020, which is a 4U 19" Rackmount case with 20 Hot Swap 3.5" SATA/SAS Hdd trays (Backplanes included) and room for two 2.5" OS drives as well as a Slim Line CD-Rom. The backplanes connect with a single SATA port for each drive, so there are 20 internal SATA ports to to be connected. They also have redundant power ports which I think is quite nice. The cheapest price I have found is 290$ + 40$ shipping. In europe the cheapest unfortunately is 370€ (500$) + 40 € shipping... A nice alternative would be the RPC-4224 which has SFF-8087 Mini SAS connectors that bundle 4 SATA trays each. But it doesn't seem to be available in Europe (where i am) anywhere. So here comes my problem: What Mainboard/Controller to choose to connect them for as cheap as possible while still having nice data rates? I have to say that the server is intended as a Storage server with 1gps connectivity and the data transfer will be distributed very evenly across all drives. I also don't require any raid functionality. This is all done at application level, I just need JBOD. So for example if I go for the RPC 4020 Model I need to connect 20 Storage + 1 OS + 1 CDROM Sata ports. I searched a bit and stumbled across this very low priced controller: http://www.intel.com/products/server/raid-controllers/SASWT4I/SASWT4I-overview.htm They sell it for 115 € here and the specs say it can control up to 122 hard discs and has 4 Mini SAS connectors. So I would use 4 Mini SAS 36pin - 4 SATA 7pin cables to connect 4 SATA drives to each port and choose a Mainboard taht has 6 SATA on board (for example this one) and hurray, I can connect my 22 SATA devices for as low as about ~ 220 EUR (cpu, ram, psu, case not counted) Question: WOULD THAT WORK? And if not, why? 2nd Question: If I go for the 4220 or 4224 Model, I have internal Mini SAS connectors. Am I right in assuming that the backplane than acts as a "SAS Expander"? And can I just plug these SAS connectors into any SAS port I can find on my controller / mainboard or are there certain requirements? I know that SATA port multipliers only work with controllers that are ready for that. But isn't this expansion already implemented in the SAS standard? I am sorry that this is a very broad question, but I really spent the last week reading up and it seems to be not so clear! Especially all the controlling hardware specifications! 3rd Question: A lot of hardware specs feature "internal channels" and "internal connectors". The connecors are the physical numbers of places where I can plug a cable in. I got that. But are the "internal channels" always the maximum numbers of physical drives that can be used in the end? Or can I enhance this further by Expanders/Fanouts? 4th and last question: What do you think about the setup so far? Do you know any good alternatives? Maby I am completely going the wrong way and some DAS would be way better? Are there any comparable chassis available in europe? Please feel free to say whatever you think is relevant to the subject!

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• Outlook 2013 keeps freezing, semi-consistently

  - by AviD

  I have an oddity of problem with my Outlook's stability. It seems to be freezing up, not at random intervals, but based on a seemingly strange combination of configurations. I have been trying many different combinations, I've even devolved to "Cargo-cult" debugging, since I have no clue what is causing this... Here is my set up - since I don't know for sure which settings are causing the lockup, I'll probably mention irrelevant things: (relatively) clean install of Windows 8 (on hyper-v, if that matters) Clean install of Outlook 2013, fully updated 3 accounts configured: Hotmail account configured with ActiveSync Gmail account Large-ish account (several GB) connected with IMAP Only a few folders are subscribed in IMAP Outlook is set to only display subscribed folders configured to keep messages permanently Google Apps account, connected with IMAP Small account connected with IMAP All folders IMAP subscribed Outlook is set to only display subscribed folders configured to keep messages permanently Several Send/Receive Groups configured, to try different configurations of enabling/disable/partial the different accounts - with different send times, from 60 minutes down to 5 minutes. The problem is that at certain points Outlook completely freezes up and I have to kill it. This is not consistent - there are some things that cause it immediately almost consistently, there are some times that it just happens by itself after some period of time (sometimes a few moments, sometimes a few hours; sometimes while using it, sometimes after I've been away from it for a few hours). I have searched all over, and there seem to be many with similar (apparently) problem, and found numerous "solutions" (some even more cargocultish than mine), but so far none of them worked. I've removed all the accounts, both all together and one at a time, and re-configured them - eventually it freezes up. I've tried uninstalling Outlook, cleaning it up completely - removing files, app settings, registry keys, etc - then reinstalling - eventually it freezes up. I've only enabled the Hotmail account, disabling (but not removing) the Google accounts - apparently this does not lock up. I've enabled the Hotmail and the Gmail accounts, leaving the Apps one disabled - it seems like it does not lock up. With all accounts enabled, it locks up almost immediately after doing a send/receive. With only the Apps account enabled, it seems to not lock up. With the Hotmail and the Apps accounts enabled (Gmail disabled), it seems like it locks up after a random amount of time. With Hotmail enabled, and Gmail and Apps both enabled but set to receive only custom folder downloading (not all subscribed folders) - sometimes it locks up right after a send/receive, sometimes it goes for hours without locking up, and sometimes it only locks up when I send an email. I've tried switching the ports for the Google accounts (SSL/465 vs TLS/587), though I have no idea if this should affect, but no real difference. In short, I honestly have no idea what is actually causing Outlook to lock up, I might be completely barking up the wrong tree. At this point I don't really know what else to try, I'm flipping switches at random here. I would like to have all 3 accounts enabled, ideally in several groups (e.g. pull down only important folders in a group with short interval, and all other folders in a longer interval) - obviously without freezing up at all. I've tried putting in all the important details, if there is anything else important to add please let me know. Another issue that occurred to me might also be connected - the Google accounts don't always synchronize properly, even after a send/receive or "update folder". At least not consistently... though I haven't been able to find a significant connection between this and that.

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• What NAS setup for two-way syncing over the internet?

  - by Jamse

  I have family living a few hours away and have a lot of files that I would like to share - especially lots of folders of digital photos, but also documents etc. - partially so they can see them, partially so I can have access when I visit them and partially for backup / redundancy purposes. My current hard drives on my main machine are getting pretty full anyway, and I have a MythTV box where my music is currently stored, so I was thinking of getting a NAS anyway. And at the other end my family have a few computers, so they would probably benefit from a NAS too. My general idea (though I'm willing to shift on this if there are any bright ideas about other ways of achieving my objectives) is to get a matching pair of NASs and have them sync over the internet. (To cut down on bandwidth use I would get them in sync locally to start with.) Having read around as best I can it seems that syncing over the internet is generally only a feature on quite high end units. However, I have seen that QNAP seem to feature this on their TS-110 and TS-210 units, which might work (they call it "remote replication"). They seem pretty reasonably priced for what they are, but of course with buying 2 of them and then adding the drives (say 1TB or 2TB each) I'd be looking at about £400 total. So, I'm looking for recommendations really. I don't want to spend more than the QNAPs would cost me, but any other ideas would be most appreciated. I am comfortable with technology and tinkering around, but I don't have as much time for that as I would like, so I guess I would favour solutions that require less tinkering rather than more (even though that's less fun!). Any thoughts would be welcome, as would any comments from people who have used the QNAP boxes for this. Thanks in advance. Some specifications: Two-way syncing. Changes made at either end should be synced to the other. There shouldn't be one unit that is effectively a read-only mirror of the other. Not real time. The syncing doesn't need to be real time - if it updated, say, daily overnight that would be fine. Set and forget. I would prefer minimal user interaction once set up - it would be great if syncs were scheduled and automatic. OS independence. I am running Windows XP plus an Ubuntu-based MythTV box. At the other end there are Windows 7 and Windows XP machines, plus a networked TV set top box which I think can play files off the network. Machine independence. I would favour a system that is self-contained, i.e. not reliant on any particular PC being switched on. If the system had enough else going for it I could perhaps work around it at this end, where I only have one PC that's used as such, but it would be harder at the other where there are at least two PCs that might be accessing the files. Notifications. I guess things like getting an email notification if the syncing fell over for any reason would be useful, though it's not a deal breaker. Update I've been digging some more and it looks like QNAP's Remote Replication function is actually just Rsync, so only really suitable for one-way syncing. I've posted on their forum to double check, but I think that's the case. In which case, I think the focus of my question is now either: do any reasonably-priced NASs support bidirectional syncing over the internet?, or has anyone had any luck installing onto NASs for this purpose? (Also, updated question to clarify that I'm after two-way syncing.)

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• Supermicro IPMI on MBD-X8DAH+-F-O motherboard. Keyboard and mouse do not work after booting Windows Server 2008 R2

  - by LDelgado

  Hell Everyone, I built a server with the mentioned motherboard. I installed Windows Server 2008 R2 Enterprise on this server. IPMI is integrated on the motherboard with its own dedicated NIC. I've got that NIC configured with its own IP address. I can remote into it using IPMI, and I can remotely control the server settings before booting the OS ( BIOS, RAID configuration, etc). When the OS boots, I lose the mouse and keyboard. I cannot use the keyboard or mouse when installing the OS either. So the Keyboard and Mouse only work when no OS is loaded. Once the OS loads I lose it - that is my problem. I've been doing some research and trying a few things, but I have not been successful in fixing this issue. I may be wrong, but based on the things I've found online, it seems that the problem could be caused by the way the OS handles USB. The server is headless. There is no keyboard, mouse, or monitor plugged into it. When I boot up the OS and remote into it, I cannot see a mouse or keyboard listed in the Device Manager. Based on what I've read, it seems that the OS should detect a mouse and a keyboard when connecting remotely via IPMI. The following are the solutions I've tried. Nothing has worked so far: I've updated the firmware of the IPMI component to the latest firmware - 1.33. I made sure that the mouse mode was set to Absolute (Windows OS). I've loaded the factory defaults several times. I've enabled Port64h/60h Emulation under the USB settings in the BIOS. I've disabled USB legacy support in the BIOS. I made sure the firewall wasn't blocking IPMI (disabled the firewall). And that's about it. I've found threads in some forums from people having the same issue as me, but they were not running the same OS. They were either running Linux or FreeBSD. Most of them fixed their problem by selecting the right mouse mode (Linux in their case). There was one other that solved the problem by disabling USB Mass Storage mode. He stated "When I set it to disable USB Mass Storage when no image is loaded, the ukbd came alive, and I'm typing this on the IPMI Console. " source: http://freebsd.1045724.n5.nabble.com/IPMI-Console-No-luck-once-OS-is-booted-td3967868.html I suspect the solution described in the previous paragraph is somehow related to my problem. I've found several threads on the internet with issues describing the same problem, but none of them were with Windows Server 2008 R2. Again, I may be wrong, but it seems like that could be the issue. I just don't know how I go about applying a solution in Windows Server 2008 R2. In any case, I could use your expertise. Maybe I am missing something, or maybe I'm on the right track. Your help is much appreciated. Thank you in advance,

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• File copying utility like rsync with error handling like ddrescue, for data recovery from a hard drive with bad sectors or hardware failure

  - by purefusion

  I have a hard drive with either bad blocks or sectors that are failing to read due to potential mechanical issues, such as a bad disk head, bad motor, or some other issue that is causing the hard drive to read data excruciatingly slowly and with lots of read errors. I'm seeing an average of 50 KB/sec, with some reads dropping below 10 KB/sec, and frequently it gets stuck on a file or sector altogether, usually for quite a long time—from 2-10 minutes or more (when using rsync, before it times out). Speed seems to vary wildly, and it gets stuck on files a lot, and when it finally gets "unstuck" it only seems to last for a short burst before it gets stuck again. The drive is also very quiet with only an occasional sound of files copying (usually when it gets stuck/unstuck for a brief time, before getting stuck again). Thus, there are none of those evil sounds that are normally associated with HDD death. Someone suggested that the problems sounded like they might be caused by a misaligned disk head, which requires a lot of re-reads before it finally reads data with success. Sounds plausible, but I digress... Anyway, the problem with rsync is that it seems to have no decent error handling support. Obviously, it wasn't meant for use in recovering data from failing hard drives, but all the so-called "data recovery" utilities out there that are meant for such use usually focus on recovery of deleted files or messed up partitions, rather than copying files off dying hard drives. Deleted file recovery is not what I need, obviously, so perhaps you can understand my disappointment in not being able to find what I'm after yet. Naturally, this is where you'd probably say "You should use ddrescue!" Well, that's all fine and dandy, but I've already got most of the data backed up, so I just want to recover certain files. I'm not concerned with trying to recover a full partition block-by-block as ddrescue does. I am only interested in rescuing just specific files and directories. Ideally, what I'd like is some sort of cross between rsync and ddrescue: something that lets me specify source and destination as directories of normal files like rsync (rather than two full partitions as ddrescue requires), with a way to skip files with errors in an initial run, and then allows me to attempt recovery of those files with errors in a later run (with a slightly altered command, of course), perhaps even offering an option to specify the number of retry attempts ...just like how ddrescue works with blocks, only I want a utility that works with specific files/directories like rsync does. So am I daydreaming here, or does something out there exist that can do this? Or, maybe even a way to make rsync or ddrescue work in such a way? I'm really open to whatever solutions might work, so long as they let me choose which files I want to "rescue", and can skip files with errors in the initial run, and try/retry those errors again later. So far I've tried rsync with the following options, but it often gets stuck on a file for longer than the timeout, and ideally I'd just like it to move on to the next file and come back later to the files it gets stuck on. I don't think that's possible though. Anyway, here's what I've been using up till now: rsync -avP --stats --block-size=512 --timeout=600 /path/to/source/* /path/to/destination/

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• Why are USB 2.0 devices crashing my system?

  - by BenAlabaster

  Background on the machine I'm having a problem with: The machine was inherited and appears to be circa 2003 (there's a date stamp on the power supply which leads me to this conclusion). I've got it set up as a Skype terminal for my 2 year old to keep in touch with her grandparents and other members of the family - which everyone loves. It has a generic baby-ATX motherboard with no identifying markings. CPU-Z identifies the motherboard model as VT8601 but doesn't provide me with any manufacturer name. There's one stamp on the motherboard that says "Rev.B". On board it has 10/100 LAN, 2 x USB 1.0, VGA, PS/2 for KB and mouse, parallel port, 2 x serial ports, 2 x IDE, 1 x floppy, 2 x SDRAM slots, 1 x CPU housing that is seating a 1.3GHz Intel Celeron CPU, 3 x PCI, 1 x AGP - although you can only use 2 of the PCI slots if you use the AGP slot due to the physical layout of the board. It's got 768Mb PC133 SDRAM - 1 x 512Mb & 1 x 256Mb installed as well as a D-LINK WDA-2320 54G Wi-Fi network card and a generic USB 2.0 expansion board containing 3 x external + 1 x internal USB connectors. All this is sitting in a slimline case. I don't know the wattage of the PSU, but can post this later if this proves to be helpful. The motherboard is running a version of Award BIOS for which I don't have the version number to hand but can again post this later if it would be helpful. It has an 80Gb Western Digital hard drive freshly formatted and built with Windows XP Professional with Service Pack 3 and all current patches. In addition to Windows XP, the only other software it's running is Skype 4.1 (4.2 crashes the machine as soon as it starts up). It's got a Daytek MV150 15" touch screen running through the VGA and COM1 with the most current drivers from the Daytek website and the most current version of ELO-Touchsystems drivers for the touch component. The webcam is a Logitech Webcam C200 with the latest drivers from the Logitech website. The problem If I hook any USB 2.0 devices to this machine, it hangs the whole machine and I have to hard boot it to get it back up. Workarounds found I can plug the same devices into the on board USB 1.0 connectors and everything works fine, albeit at reduced performance. I've tried 3 different kinds of USB thumb drives, 3 different makes/models of webcams and my iPhone all with the same effect. They're recognized and don't hang the machine when I hook them to the USB 1.0 but if I hook them to the USB 2.0 ports, the machine hangs within a couple of seconds of recognizing the devices were connected. Attempted solutions I've tried disabling all the on board devices that I'm not using - such as the on board LAN, the second COM port, the AGP connector etc. through the BIOS in an (perhaps misguided or futile) attempt to reduce the power consumption... I don't think it had any effect but it didn't do any harm. I was wondering if the PSU wattage just isn't enough to drive the USB 2.0 devices; I've seen this suggested but haven't found any confirmation that this could really be an issue - nor have I found a way to work around this issue - if indeed it is one. Any ideas? The only thing I haven't done which I only just thought of while writing this essay is trying the USB 2.0 card in a different PCI slot, or re-ordering the wi-fi and USB cards in the slots... although I'm not sure if this will make any difference. I've installed the USB card in another machine and it works without issue, so it's not a problem with the USB card itself. Other thoughts Perhaps this is an incompatibility between the USB 2.0 card and the BIOS, would re-flashing the BIOS with a newer version help? Do I need to be able to identify the manufacturer of the motherboard in order to be able to find a BIOS edition specific for this motherboard or will any version of Award BIOS function in its place? Question Does anyone have any ideas that could help me get my USB 2.0 devices hooked up to this machine?

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• What NAS setup for syncing over the internet?

  - by Jamse

  I have family living a few hours away and have a lot of files that I would like to share - especially lots of folders of digital photos, but also documents etc. - partially so they can see them, partially so I can have access when I visit them and partially for backup / redundancy purposes. My current hard drives on my main machine are getting pretty full anyway, and I have a MythTV box where my music is currently stored, so I was thinking of getting a NAS anyway. And at the other end my family have a few computers, so they would probably benefit from a NAS too. My general idea (though I'm willing to shift on this if there are any bright ideas about other ways of achieving my objectives) is to get a matching pair of NASs and have them sync over the internet. (To cut down on bandwidth use I would get them in sync locally to start with.) Having read around as best I can it seems that syncing over the internet is generally only a feature on quite high end units. However, I have seen that QNAP seem to feature this on their TS-110 and TS-210 units, which might work (they call it "remote replication"). They seem pretty reasonably priced for what they are, but of course with buying 2 of them and then adding the drives (say 1TB or 2TB each) I'd be looking at about £400 total. So, I'm looking for recommendations really. I don't want to spend more than the QNAPs would cost me, but any other ideas would be most appreciated. I am comfortable with technology and tinkering around, but I don't have as much time for that as I would like, so I guess I would favour solutions that require less tinkering rather than more (even though that's less fun!). Any thoughts would be welcome, as would any comments from people who have used the QNAP boxes for this. Thanks in advance. Some specifications: Two-way syncing. Changes made at either end should be synced to the other. There shouldn't be one unit that is effectively a read-only mirror of the other. Not real time. The syncing doesn't need to be real time - if it updated, say, daily overnight that would be fine. Set and forget. I would prefer minimal user interaction once set up - it would be great if syncs were scheduled and automatic. OS independence. I am running Windows XP plus an Ubuntu-based MythTV box. At the other end there are Windows 7 and Windows XP machines, plus a networked TV set top box which I think can play files off the network. Machine independence. I would favour a system that is self-contained, i.e. not reliant on any particular PC being switched on. If the system had enough else going for it I could perhaps work around it at this end, where I only have one PC that's used as such, but it would be harder at the other where there are at least two PCs that might be accessing the files. Notifications. I guess things like getting an email notification if the syncing fell over for any reason would be useful, though it's not a deal breaker.

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• Capistrano + Nginx + Passenger = 403

  - by slimchrisp

  I asked this over at stackoverflow as well, but still haven't received any answers that have helped me to solve this problem. I have spent almost a week at this point trying to solve the issue, and I'm just not making any headway. It seems that this issue is pretty common, but none of the solutions I found online work for me. A buddy of mine is actually creating the same setup, and he is having the same issue. After a few days stuck with the 403 error I started over using this tutorial: http://blog.ninjahideout.com/posts/a-guide-to-a-nginx-passenger-and-rvm-server I had hoped starting from scratch using this tutorial would work, but no dice. Either way, if you view the tutorial you can see what steps I have taken. Here is essentially what I have going on. I have a VPS account on linode.com Server OS is Ubuntu 10.04 Local OS (shouldn't matter, but just so you know) used to deploy with Capistrano is Snow Leopard 10.6.6 I use RVM on the server. Version is 1.2.2 I was previously on ruby-1.9.2-p0 [ i386 ], but per the tutorial listed above I switched to ree-1.8.7-2010.02 [ i386 ]. Running 'which ruby' from the command line verifies that I am using 1.8.7 with the following output: /usr/local/rvm/rubies/ree-1.8.7-2010.02/bin/ruby passenger -v prints the following: Phusion Passenger version 3.0.2 Running 'nginx -v' gives me a message that the command nginx could not be found. The server is definitely there and running as I can use nginx to serve static files, but this could have something to do with my problem. I have two users dealing with the install. root which I used to install everything, and deployer which is a user I created specifically to for deploying my applications My web app directory is in the deployer user's home directory as follows: /home/deployer/webapps/mysite.com/public Per Capistrano default deploy, a symbolic link called current is created in the public folder, and points to /home/deployer/webapps/mysite.com/public/releases/most_current_release I have chmodded the deployer directory recursively to 777 /opt/nginx permissions: rwxr-xr-x /usr/local/rvm/gems/ree-1.8.7-2010.02/gems/passenger-3.0.2 permissions: rwxrwsrwx My nginx config file has gone through just short of eternity variations, but currently looks like this: ================================================================================== worker_processes 1; events { worker_connections 1024; } http { passenger_root /usr/local/rvm/gems/ree-1.8.7-2010.02/gems/passenger-3.0.2; passenger_ruby /usr/local/rvm/bin/passenger_ruby; include mime.types; default_type application/octet-stream; sendfile on; keepalive_timeout 65; server { # listen *:80; server_name mysite.com www.mysite.com; root /home/deployer/webapps/mysite.com/public/current; passenger_enabled on; passenger_friendly_error_pages on; access_log logs/mysite.com/server.log; error_log logs/mysite.com/error.log info; error_page 500 502 503 504 /50x.html; location = /50x.html { root html; } } } ================================================================================== I bounce nginx, hit the site, and boom. 403, and logs say directory index of /home/deployer... is forbidden As others with a similar problem have said, you can drop an index.html into the public/releases/current_release and it will render. But rails no worky. That's basically it. At this point I have just about completely exhausted every possible solution attempt I can think of. I am a programmer and definitely not a sysadmin, so I am 99% sure this has something to do with permissions that I have hosed, but for the life of me I just can't figure out where. If anyone can help I would really really appreciate it. If there's any specific permission things you want me to check (ie groups/permissions), can you please include the commands to do so as well. Hopefully this will help others in the future who read this post. Let me know if there is any other information I can provide, and thanks in advance!!!

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• Pushing DNSSEC updates with offline keys

  - by eggyal

  In a non-professional capacity, I look after the DNS of some 18 domains: mostly personal/vanity domains for immediate family. I outsource the whole shebang to an inexpensive managed hosting provider with a web interface through which I manage the zones; since the provider also offers DNSSEC, I have successfully deployed that too. These domains are so unimportant that an attack targetted against them seems much less likely than a general compromise of my provider's systems, at which point the records of all their customers might be changed to misdirect traffic (perhaps with extremely long TTLs). DNSSEC could protect against such an attack, but only if the zone's private keys are not held by the hosting provider. So, I wonder: how can one keep DNSSEC private keys offline yet still transfer signed zones to an outsourced DNS host? The most obvious answer (to me, at least) is to run one's own shadow/hidden master (from which the provider can slave) and then copy offline-signed zonefiles to the master as required. The problem is that the only machine I (want to*) control is my personal laptop, which usually connects from a typical home ADSL (behind NAT over a dynamically-assigned IP address). Having them slave from that (e.g. with a very long Expiry time on the zone for periods when my laptop is offline/unavailable) would not only require a Dynamic DNS record from which they can slave (if indeed they can slave from a named host rather than a static IP address), but would also involve me running a DNS server on my laptop and opening both it and my home network up to the incoming zone transfer requests: not ideal. I would prefer a much more push-oriented design, whereby my laptop initiates transfer of offline-signed zonefiles/updates to the provider's servers. I looked into whether nsupdate could fit the bill: documentation is a little sketchy, but my testing (with BIND 9.7) suggests it can indeed update DNSSEC zones, but only where the server holds the keys to perform the zone signing; I have not found a way to have it take an update including the relevant RRSIG/NSEC/etc. records and have the server accept them. Is this a supported use-case? If not, I suspect the only solutions which could fit the bill will involve non-DNS-based transfer of the zone updates and would welcome recommendations that are supported by (hopefully inexpensive) hosting providers: SFTP/SCP? rsync? RDBMS replication? Proprietary API? Finally, what would be the practical implications of such a setup? Key rotation is jumping out at me as being an obvious difficulty, especially if my laptop is offline for extended periods. But the zones are extremely stable, so perhaps I could get away with long-lived ZSKs**...? * Whilst I could run a shadow/hidden master on e.g. an outsourced VPS, I dislike the overhead of having to secure / manage / monitor / maintain yet another system; not to mention the additional financial costs of so doing. ** Okay, this would enable a concerted attacker to replay outdated records—but the risk and impact of such are both tolerable in the case of these domains.

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• SQL Server 2000 and SSL Encryption

  - by Angry_IT_Guru

  We are a datacenter that hsots a SQL Server 2000 environment which provides database services for a product we sell that is loaded as a rich-client applicatin at each of our many clients and their workstations. Currently today, the application uses straight ODBC connections from the client site to our datacenter. We need to begin encrypting the credentials -- since everything is clear-text today and the authentication is weakly encrypted -- and I'm trying to determine the best way to implement SSL on the server with minimizing the impact of the client. A few things, however: 1) We have our own Windows domain and all our servers are joined to our private domain. Our clietns no nothing of our domain. 2) Typically, our clients connect to our datacenter servers either by: a) Using TCP/IP address b) Using a DNS name that we publish via internet, zone transfers from our DNS servers to our customers, or the client can add static HOSTS entries. 3) From what I understand from enabling encryption is that I can go to the Network Utility and select the "encryption" option for the protocol that I wish to encrypt. Such as TCP/IP. 4) When the encryption option is selected, I have a choice of installing a third-party certificate or a self-signed. I have tested the self-signed, but do have potential issues. I'll explain in a bit. If I go with a third-party cert, such as Verisign, or Network solutions... what kind of certificate do I request? These aren't IIS certificates? When I go create a self-signed via Microsoft's certificate server, I have to select "Authentication certificate". What does this translate to in the third-party world? 5) If I create a self-signed certificate, I understand that the "issue to" name has to match the FQDN for the server that is running SQL. In my case, I have to use my private domain name. If I use this, what does this do for my clients when trying to connect to my SQL Server? Surely they cannot resolve my private DNS names on their network.... I've also verified that when the self-signed certificate is installed, it has to be in the local personal store for the user account that is running SQL Server. SQL Server will only start if the FQDN matches the "issue to" of the certificate and SQL is running under the account that has the certificate installed. If I use a self-signed certificate, does this mean I have to have every one of my clients install it to verify? 6) If I used a third-party certificate, which sounds like the best option, do all my clients have to have internet access when accessing my private servers of their private WAN connection to use to verify the certificate? What do I do about the FQDN? It sounds like they have to use my private domain name -- which is not published -- and can no longer use the one that I setup for them to use? 7) I plan on upgrading to SQL 2000 soon. Is setup of SSL any easier/better with SQL 2005 than SQL 2000? Any help or guiadance would be appreciated

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• PHP, Apache and curl: Differences between Windows and Linux?

  - by beginner_

  I'm trying to run my php App on Ubuntu Server 11.10. This App works fine under Apache + PHP in windows. I have other applications that I can simply copy&paste between the 2 OS and they work on both. (These don't use cURL). However this one uses the php library tonic (RESTful webservices) and makes us of php cURL module. The issue is I'm not getting an error message which makes it impossible to find the issue. I (must) use NTLM authentication and this is done with AuthenNTLM Apache Module: Order allow,deny Allow from all PerlAuthenHandler Apache2::AuthenNTLM AuthType ntlm AuthName "Protected Access" require valid-user PerlAddVar ntdomain "domainName server" PerlSetVar defaultdomain domainName PerlSetVar ntlmsemtimeout 2 PerlSetVar ntlmdebug 1 PerlSetVar splitdomainprefix 0 All files that cURL needs to fetch override AuthenNTLM authentication: order deny,allow deny from all allow from 127.0.0.1 Satisfy any Since these files are only fectehd by cURL from same server, access can be limited to localhost. Possible issues are: NTLM auth isn't overridden for files requested through cURL (even though AllowOverride All is set) curl works differently on linux $ch = curl_init(); curl_setopt($ch, CURLOPT_COOKIE, $strCookie); curl_setopt($ch, CURLOPT_URL, $baseUrl . $queryString); curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1); $html = curl_exec($ch); curl_close($ch); other? Apache log says: [error] Bad/Missing NTLM/Basic Authorization Header for /myApp/webservice/local/viewList.php But this directory should override NTLM authentication using curl command line from windows to access same resource i get: <!DOCTYPE HTML PUBLIC "-//IETF//DTD HTML 2.0//EN"> <html> <head> <title>406 Not Acceptable</title> </head> <body> <h1>Not Acceptable</h1> <p>An appropriate representation of the requested resource /myApp/webservice/myResource could not be found on this server.</p> Available variants: <ul> <li><a href="myResource.php">myResource.php</a> , type application/x-httpd-php</li> </ul> <hr> <address>Apache/2.2.20 (Ubuntu) Server at localhost Port 80</address> </body> </html> Note: This is duplicate from http://stackoverflow.com/questions/9821979/php-curl-on-linux-what-is-the-difference-to-curl-on-windows Is it was suggested I post it here. EDIT: Please see Ubuntu Server: Apache2 seems to attach .php to URI as I discovered why it does not work but need help so the issue does not occur anymore. ANSWER: The issue is the default Apache configuration on Ubuntu: Options Indexes FollowSymLinks MultiViews MultiViews is changing request_uri from myResource to myResource.php. Solutions: disable MultiViews in .htaccess: Options -MultiViews remove MultiViews from default config rename the file as example to myResourceClass I chose last option because that should work regardless of configuration and I only have 3 such files so the change took about 30 secs...

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• Log transport and aggregation at scale

  - by markdrayton

  How're you analysing log files from UNIX/Linux machines? We run several hundred servers which all generate their own log files, either directly or through syslog. I'm looking for a decent solution to aggregate these and pick out important events. This problem breaks down into 3 components: 1) Message transport The classic way is to use syslog to log messages to a remote host. This works fine for applications that log into syslog but less useful for apps that write to a local file. Solutions for this might include having the application log into a FIFO connected to a program to send the message using syslog, or by writing something that will grep the local files and send the output to the central syslog host. However, if we go to the trouble of writing tools to get messages into syslog would we be better replacing the whole lot with something like Facebook's Scribe which offers more flexibility and reliability than syslog? 2) Message aggregation Log entries seem to fall into one of two types: per-host and per-service. Per-host messages are those which occur on one machine; think disk failures or suspicious logins. Per-service messages occur on most or all of the hosts running a service. For instance, we want to know when Apache finds an SSI error but we don't want the same error from 100 machines. In all cases we only want to see one of each type of message: we don't want 10 messages saying the same disk has failed, and we don't want a message each time a broken SSI is hit. One approach to solving this is to aggregate multiple messages of the same type into one on each host, send the messages to a central server and then aggregate messages of the same kind into one overall event. SER can do this but it's awkward to use. Even after a couple of days of fiddling I had only rudimentary aggregations working and had to constantly look up the logic SER uses to correlate events. It's powerful but tricky stuff: I need something which my colleagues can pick up and use in the shortest possible time. SER rules don't meet that requirement. 3) Generating alerts How do we tell our admins when something interesting happens? Mail the group inbox? Inject into Nagios? So, how're you solving this problem? I don't expect an answer on a plate; I can work out the details myself but some high-level discussion on what is surely a common problem would be great. At the moment we're using a mishmash of cron jobs, syslog and who knows what else to find events. This isn't extensible, maintainable or flexible and as such we miss a lot of stuff we shouldn't. Updated: we're already using Nagios for monitoring which is great for detected down hosts/testing services/etc but less useful for scraping log files. I know there are log plugins for Nagios but I'm interested in something more scalable and hierarchical than per-host alerts.

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• Is there a bug with Apache 2.2 and content filters (and maybe mod_proxy)?

  - by asciiphil

  I'm running Apache 2.2.15-29 on RHEL 6 (actually Scientific Linux 6.4) and I'm trying to set up a reverse proxy with content rewriting so all of the links on the proxied web pages are rewritten to reference the proxy host. I'm running into a problem with some of the content rewriting and I'd like to know if this is a bug or if I'm doing something wrong (and how to do it right, if applicable). I'm proxying a subdirectory on an internal host (internal.example.com/foo) onto the root of an external host (external.example.com). I need to rewrite HTML, CSS, and Javascript content to fix all of the URLs. I'm also hosting some content locally on the external host, which I don't think is a problem but I'm mentioning here for completeness. My httpd.conf looks roughly like this: <VirtualHost *:80> ServerName external.example.com ServerAlias example.com # Serve all local content directly, reverse-proxy all unknown URIs. RewriteEngine On RewriteRule ^(/(index.html?)?)?$ http://internal.example.com/foo/ [P] RewriteCond %{DOCUMENT_ROOT}%{REQUEST_FILENAME} -f [OR] RewriteCond %{DOCUMENT_ROOT}%{REQUEST_FILENAME} -d RewriteRule ^.*$ - [L] RewriteRule ^/~ - [L] RewriteRule ^(.*)$ http://internal.example.com$1 [P] # Standard header rewriting. ProxyPassReverse / http://internal.example.com/foo/ ProxyPassReverseCookieDomain internal.example.com external.example.com ProxyPassReverseCookiePath /foo/ / # Strip any Accept-Encoding: headers from the client so we can process the pages # as plain text. RequestHeader unset Accept-Encoding # Use mod_proxy_html to fix URLs in text/html content. ProxyHTMLEnable On ProxyHTMLURLMap http://internal.example.com/foo/ / ProxyHTMLURLMap http://internal.example.com/foo / ProxyHTMLURLMap /foo/ / ## Use mod_substitute to fix URLs in CSS and Javascript #<Location /> # AddOutputFilterByType SUBSTITUTE text/css # AddOutputFilterByType SUBSTITUTE text/javascript # Substitute "s|http://internal.example.com/foo/|/|nq" #</Location> # Use mod_ext_filter to fix URLs in CSS and Javascript ExtFilterDefine fixurlcss mode=output intype=text/css cmd="/bin/sed -rf /etc/httpd/fixurls" ExtFilterDefine fixurljs mode=output intype=text/javascript cmd="/bin/sed -rf /etc/httpd/fixurls" <Location /> SetOutputFilter fixurlcss;fixurljs </Location> </VirtualHost> The text/html rewriting works just fine. When I use either mod_substitute or mod_ext_filter, the external server sends the pages as Transfer-Encoding: chunked, sends all of the data, and then closes the connection without sending the final, zero-length chunk. Some HTTP clients are unhappy with this. (Chrome won't process any content sent in this way, for example, so the pages don't get CSS applied to them.) Here's a sample wget session: $ wget -O /dev/null -S http://external.example.com/include/jquery.js --2013-11-01 11:36:36-- http://external.example.com/include/jquery.js Resolving external.example.com (external.example.com)... 192.168.0.1 Connecting to external.example.com (external.example.com)|192.168.0.1|:80... connected. HTTP request sent, awaiting response... HTTP/1.1 200 OK Date: Fri, 01 Nov 2013 15:36:36 GMT Server: Apache Last-Modified: Tue, 29 Oct 2013 13:09:10 GMT ETag: "1d60026-187b8-4e9e0ec273e35" Accept-Ranges: bytes Vary: Accept-Encoding X-UA-Compatible: IE=edge,chrome=1 Content-Type: text/javascript;charset=utf-8 Connection: close Transfer-Encoding: chunked Length: unspecified [text/javascript] Saving to: `/dev/null' [ <=> ] 100,280 --.-K/s in 0.005s 2013-11-01 11:36:37 (19.8 MB/s) - Read error at byte 100280 (Success).Retrying. --2013-11-01 11:36:38-- (try: 2) http://external.example.com/include/jquery.js Connecting to external.example.com (external.example.com)|192.168.0.1|:80... connected. HTTP request sent, awaiting response... HTTP/1.1 416 Requested Range Not Satisfiable Date: Fri, 01 Nov 2013 15:36:38 GMT Server: Apache Vary: Accept-Encoding Content-Type: text/html;charset=utf-8 Content-Length: 260 Connection: close The file is already fully retrieved; nothing to do. Am I doing something wrong? Am I hitting some sort of Apache bug? What do I need to do to get it working? (Note that I'd prefer solutions that work within RHEL-6-packaged RPMs and upgrading to Apache 2.4 would be a last resort, as we have a lot of infrastructure built around 2.2 on this system at the moment.)

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• how to remove obsolete device and network entries? Device manager "uninstall" option has no effect

  - by Gizmo

  I am trying to remove a few "obsolete" things which annoy me (because I like to have everything cleen, working and not interferring with each other, fresh, etc..). I tried looking for solutions without any help, so here I am to ask. My first part is about removing obsolete networks, let me explain by showing the ipconfig output: C:\windows\system32>ipconfig Windows IP Configuration Wireless LAN adapter Local Area Connection* 11: Media State . . . . . . . . . . . : Media disconnected Connection-specific DNS Suffix . : Wireless LAN adapter Local Area Connection* 9: Media State . . . . . . . . . . . : Media disconnected Connection-specific DNS Suffix . : Ethernet adapter LAN: Media State . . . . . . . . . . . : Media disconnected Connection-specific DNS Suffix . : Wireless LAN adapter Wi-Fi: Connection-specific DNS Suffix . : home Link-local IPv6 Address . . . . . : fe80::c129:8d57:bbd1:3564%10 IPv4 Address. . . . . . . . . . . : 192.168.2.1 Subnet Mask . . . . . . . . . . . : 255.255.255.0 Default Gateway . . . . . . . . . : 192.168.2.254 Tunnel adapter isatap.home: Media State . . . . . . . . . . . : Media disconnected Connection-specific DNS Suffix . : home C:\windows\system32> Specificalyy the first two adapter entries annoy me because the adapters are not visible in the network connection menu (invisible folder / file visibility set to "show"): And here is the second problem altogether with the first one: No matter what I click/do, Uninstall option has no effect on the multiplexor driver. (bridging stuff, right?) I really want to remove the Wireless LAN adapter Local Area Connection entries and the adapter multiplexor stuff but it's impossible? Why is this? How can I remove them anyway?

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• From Binary to Data Structures

  - by Cédric Menzi

  Table of Contents Introduction PE file format and COFF header COFF file header BaseCoffReader Byte4ByteCoffReader UnsafeCoffReader ManagedCoffReader Conclusion History This article is also available on CodeProject Introduction Sometimes, you want to parse well-formed binary data and bring it into your objects to do some dirty stuff with it. In the Windows world most data structures are stored in special binary format. Either we call a WinApi function or we want to read from special files like images, spool files, executables or may be the previously announced Outlook Personal Folders File. Most specifications for these files can be found on the MSDN Libarary: Open Specification In my example, we are going to get the COFF (Common Object File Format) file header from a PE (Portable Executable). The exact specification can be found here: PECOFF PE file format and COFF header Before we start we need to know how this file is formatted. The following figure shows an overview of the Microsoft PE executable format. Source: Microsoft Our goal is to get the PE header. As we can see, the image starts with a MS-DOS 2.0 header with is not important for us. From the documentation we can read "...After the MS DOS stub, at the file offset specified at offset 0x3c, is a 4-byte...". With this information we know our reader has to jump to location 0x3c and read the offset to the signature. The signature is always 4 bytes that ensures that the image is a PE file. The signature is: PE\0\0. To prove this we first seek to the offset 0x3c, read if the file consist the signature. So we need to declare some constants, because we do not want magic numbers.   private const int PeSignatureOffsetLocation = 0x3c; private const int PeSignatureSize = 4; private const string PeSignatureContent = "PE";   Then a method for moving the reader to the correct location to read the offset of signature. With this method we always move the underlining Stream of the BinaryReader to the start location of the PE signature.   private void SeekToPeSignature(BinaryReader br) { // seek to the offset for the PE signagure br.BaseStream.Seek(PeSignatureOffsetLocation, SeekOrigin.Begin); // read the offset int offsetToPeSig = br.ReadInt32(); // seek to the start of the PE signature br.BaseStream.Seek(offsetToPeSig, SeekOrigin.Begin); }   Now, we can check if it is a valid PE image by reading of the next 4 byte contains the content PE.   private bool IsValidPeSignature(BinaryReader br) { // read 4 bytes to get the PE signature byte[] peSigBytes = br.ReadBytes(PeSignatureSize); // convert it to a string and trim \0 at the end of the content string peContent = Encoding.Default.GetString(peSigBytes).TrimEnd('\0'); // check if PE is in the content return peContent.Equals(PeSignatureContent); }   With this basic functionality we have a good base reader class to try the different methods of parsing the COFF file header. COFF file header The COFF header has the following structure: Offset Size Field 0 2 Machine 2 2 NumberOfSections 4 4 TimeDateStamp 8 4 PointerToSymbolTable 12 4 NumberOfSymbols 16 2 SizeOfOptionalHeader 18 2 Characteristics If we translate this table to code, we get something like this:   [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Unicode)] public struct CoffHeader { public MachineType Machine; public ushort NumberOfSections; public uint TimeDateStamp; public uint PointerToSymbolTable; public uint NumberOfSymbols; public ushort SizeOfOptionalHeader; public Characteristic Characteristics; } BaseCoffReader All readers do the same thing, so we go to the patterns library in our head and see that Strategy pattern or Template method pattern is sticked out in the bookshelf. I have decided to take the template method pattern in this case, because the Parse() should handle the IO for all implementations and the concrete parsing should done in its derived classes.   public CoffHeader Parse() { using (var br = new BinaryReader(File.Open(_fileName, FileMode.Open, FileAccess.Read, FileShare.Read))) { SeekToPeSignature(br); if (!IsValidPeSignature(br)) { throw new BadImageFormatException(); } return ParseInternal(br); } } protected abstract CoffHeader ParseInternal(BinaryReader br);   First we open the BinaryReader, seek to the PE signature then we check if it contains a valid PE signature and rest is done by the derived implementations. Byte4ByteCoffReader The first solution is using the BinaryReader. It is the general way to get the data. We only need to know which order, which data-type and its size. If we read byte for byte we could comment out the first line in the CoffHeader structure, because we have control about the order of the member assignment.   protected override CoffHeader ParseInternal(BinaryReader br) { CoffHeader coff = new CoffHeader(); coff.Machine = (MachineType)br.ReadInt16(); coff.NumberOfSections = (ushort)br.ReadInt16(); coff.TimeDateStamp = br.ReadUInt32(); coff.PointerToSymbolTable = br.ReadUInt32(); coff.NumberOfSymbols = br.ReadUInt32(); coff.SizeOfOptionalHeader = (ushort)br.ReadInt16(); coff.Characteristics = (Characteristic)br.ReadInt16(); return coff; }   If the structure is as short as the COFF header here and the specification will never changed, there is probably no reason to change the strategy. But if a data-type will be changed, a new member will be added or ordering of member will be changed the maintenance costs of this method are very high. UnsafeCoffReader Another way to bring the data into this structure is using a "magically" unsafe trick. As above, we know the layout and order of the data structure. Now, we need the StructLayout attribute, because we have to ensure that the .NET Runtime allocates the structure in the same order as it is specified in the source code. We also need to enable "Allow unsafe code (/unsafe)" in the project's build properties. Then we need to add the following constructor to the CoffHeader structure.   [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Unicode)] public struct CoffHeader { public CoffHeader(byte[] data) { unsafe { fixed (byte* packet = &data[0]) { this = *(CoffHeader*)packet; } } } }   The "magic" trick is in the statement: this = *(CoffHeader*)packet;. What happens here? We have a fixed size of data somewhere in the memory and because a struct in C# is a value-type, the assignment operator = copies the whole data of the structure and not only the reference. To fill the structure with data, we need to pass the data as bytes into the CoffHeader structure. This can be achieved by reading the exact size of the structure from the PE file.   protected override CoffHeader ParseInternal(BinaryReader br) { return new CoffHeader(br.ReadBytes(Marshal.SizeOf(typeof(CoffHeader)))); }   This solution is the fastest way to parse the data and bring it into the structure, but it is unsafe and it could introduce some security and stability risks. ManagedCoffReader In this solution we are using the same approach of the structure assignment as above. But we need to replace the unsafe part in the constructor with the following managed part:   [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Unicode)] public struct CoffHeader { public CoffHeader(byte[] data) { IntPtr coffPtr = IntPtr.Zero; try { int size = Marshal.SizeOf(typeof(CoffHeader)); coffPtr = Marshal.AllocHGlobal(size); Marshal.Copy(data, 0, coffPtr, size); this = (CoffHeader)Marshal.PtrToStructure(coffPtr, typeof(CoffHeader)); } finally { Marshal.FreeHGlobal(coffPtr); } } }     Conclusion We saw that we can parse well-formed binary data to our data structures using different approaches. The first is probably the clearest way, because we know each member and its size and ordering and we have control about the reading the data for each member. But if add member or the structure is going change by some reason, we need to change the reader. The two other solutions use the approach of the structure assignment. In the unsafe implementation we need to compile the project with the /unsafe option. We increase the performance, but we get some security risks.

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• Week in Geek: LastPass Rescues Xmarks Edition

  - by Asian Angel

  This week we learned how to breathe new life into an aging Windows Mobile 6.x device, use filters in Photoshop, backup and move VirtualBox machines, use the BitDefender Rescue CD to clean an infected PC, and had fun setting up a pirates theme on our computers. Photo by _nash. Weekly Feature Do you love using the Faenza icon set on your Ubuntu system but feel that there are a few much needed icons missing (or you desire a different version of a particular icon)? Then you may want to take a look at the Faenza Variants icon pack. The icons are available in the following sizes: 16px, 22px, 32px, 48px and scalable sizes. Photo by Asian Angel. Faenza Variants Random Geek Links Another week with extra link goodness to help keep you on top of the news. Photo by Asian Angel. LastPass acquires Xmarks, premium service announced Xmarks announced that it has been acquired by LastPass, a cross-platform password management service. This also means that Xmarks is now in transition from a “free” to a “freemium” business model. WikiLeaks reappears on European Net domains WikiLeaks has re-emerged on a Swiss Internet domain followed by domains in Germany, Finland, and the Netherlands, sidestepping a move that had in effect taken the controversial site off the Internet. Iran: Yes, Stuxnet hurt our nuclear program The Stuxnet worm got some big play from Iranian President Mahmoud Ahmadinejad, who acknowledged that the malware dinged his nuclear program. More Windows Rogues than Just AV – Fake Defragmenter Check Disk Don’t think for a second that rogues are limited to scareware, because as so-called products such as “System Defragmenter”, “Scan Disk” “Check Disk” prove, they’re not. Internet Explorer’s Protected Mode can be bypassed Researchers from Verizon Business have now described a way of bypassing Protected Mode in IE 7 and 8 in order to gain access to user accounts. Can you really see who viewed your Facebook profile? Rogue application spreads virally Once again, a rogue application is spreading virally between Facebook users pretending to offer you a way of seeing who has viewed your profile. More holes in Palm’s WebOS Researchers Orlando Barrera and Daniel Herrera, who both work for security firm SecTheory, have discovered a gaping security hole in Palm’s WebOS smartphone operating system. Next-gen banking Trojans hit APAC With the proliferation of banking Trojans, Web and smartphone users of online banking services have to be on constant alert to avoid falling prey to fraud schemes, warned Etay Maor, project manager for RSA Fraud Action. AVG update cripples 64-bit computers A signature update automatically deployed by the AVG virus scanner Thursday has crippled numerous computers. Article includes link to forums to fix computers affected after a restart. Congress moves to outlaw ‘mystery charges’ for Web shoppers Legislation that makes it illegal for Web merchants and so-called post-transaction marketers to charge credit cards without the card owners’ say-so came closer to becoming law this week. Ballmer Set to “Look Into” Windows Home Server Drive Extender Fiasco Tuesday’s announcement from Microsoft regarding the removal of Drive Extender from Windows Home Server has sent shock waves across the web. Google tweaks search recipe to ding scam artists Google has changed its search algorithm to penalize sites deemed to provide an “extremely poor user experience” following a New York Times story on a merchant who justified abusive behavior towards customers as a search-engine optimization tactic. Geek Video of the Week Watch as our two friends debate back and forth about the early adoption of new technology through multiple time periods (Stone Age to the far future). Will our reluctant friend finally succumb to the temptation? Photo by CollegeHumor. Early Adopters Through History Random TinyHacker Links Fix Issues in Windows 7 Using Reliability Monitor Learn how to analyze Windows 7 errors and then fix them using the built-in reliability monitor. Learn About IE Tab Groups Tab groups is a useful feature in IE 8. Here’s a detailed guide to what it is all about. Google’s Book Helps You Learn About Browsers and Web A cool new online book by the Google Chrome team on browsers and the web. TrustPort Internet Security 2011 – Good Security from a Less Known Provider TrustPort is not exactly a well-known provider of security solutions. At least not in the consumer space. This review tests in detail their latest offering. How the World is Using Cell phones An infographic showing the shocking demographics of cell phone use. Super User Questions See the great answers to these questions from Super User. I am unable to access my C drive. It says it is unable to display current owner. List of Windows special directories/shortcuts like ‘%TEMP%’ Is using multiple passes for wiping a disk really necessary? How can I view two files side by side in Notepad++ Is there any tool that automatically puts screenshots to my Dropbox? How-To Geek Weekly Article Recap Look through our hottest articles from this past week at How-To Geek. How to Create a Software RAID Array in Windows 7 9 Alternatives for Windows Home Server’s Drive Extender Why Doesn’t Disk Cleanup Delete Everything from the Temp Folder? Ask the Readers: How Much Do You Customize Your Operating System? How to Upload Really Large Files to SkyDrive, Dropbox, or Email One Year Ago on How-To Geek Enjoy reading through these awesome articles from one year ago. How To Upgrade from Vista to Windows 7 Home Premium Edition How To Fix No Aero Transparency in Windows 7 Troubleshoot Startup Problems with Startup Repair Tool in Windows 7 & Vista Rename the Guest Account in Windows 7 for Enhanced Security Disable Error Reporting in XP, Vista, and Windows 7 The Geek Note That wraps things up here for this week. Regardless of the weather wherever you may be, we hope that you have an opportunity to get outside and have some fun! Remember to keep sending those great tips in to us at [email protected]. Photo by Tony the Misfit. Latest Features How-To Geek ETC The How-To Geek Guide to Learning Photoshop, Part 8: Filters Get the Complete Android Guide eBook for Only 99 Cents [Update: Expired] Improve Digital Photography by Calibrating Your Monitor The How-To Geek Guide to Learning Photoshop, Part 7: Design and Typography How to Choose What to Back Up on Your Linux Home Server How To Harmonize Your Dual-Boot Setup for Windows and Ubuntu Hang in There Scrat! – Ice Age Wallpaper How Do You Know When You’ve Passed Geek and Headed to Nerd? On The Tip – A Lamborghini Theme for Chrome and Iron What if Wile E. Coyote and the Road Runner were Human? [Video] Peaceful Winter Cabin Wallpaper Store Tabs for Later Viewing in Opera with Tab Vault

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• C#: System.Collections.Concurrent.ConcurrentQueue vs. Queue

  - by James Michael Hare

  I love new toys, so of course when .NET 4.0 came out I felt like the proverbial kid in the candy store!  Now, some people get all excited about the IDE and it’s new features or about changes to WPF and Silver Light and yes, those are all very fine and grand.  But me, I get all excited about things that tend to affect my life on the backside of development.  That’s why when I heard there were going to be concurrent container implementations in the latest version of .NET I was salivating like Pavlov’s dog at the dinner bell. They seem so simple, really, that one could easily overlook them.  Essentially they are implementations of containers (many that mirror the generic collections, others are new) that have either been optimized with very efficient, limited, or no locking but are still completely thread safe -- and I just had to see what kind of an improvement that would translate into. Since part of my job as a solutions architect here where I work is to help design, develop, and maintain the systems that process tons of requests each second, the thought of extremely efficient thread-safe containers was extremely appealing.  Of course, they also rolled out a whole parallel development framework which I won’t get into in this post but will cover bits and pieces of as time goes by. This time, I was mainly curious as to how well these new concurrent containers would perform compared to areas in our code where we manually synchronize them using lock or some other mechanism.  So I set about to run a processing test with a series of producers and consumers that would be either processing a traditional System.Collections.Generic.Queue or a System.Collection.Concurrent.ConcurrentQueue. Now, I wanted to keep the code as common as possible to make sure that the only variance was the container, so I created a test Producer and a test Consumer.  The test Producer takes an Action<string> delegate which is responsible for taking a string and placing it on whichever queue we’re testing in a thread-safe manner: 1: internal class Producer 2: { 3: public int Iterations { get; set; } 4: public Action<string> ProduceDelegate { get; set; } 5: 6: public void Produce() 7: { 8: for (int i = 0; i < Iterations; i++) 9: { 10: ProduceDelegate(“Hello”); 11: } 12: } 13: } Then likewise, I created a consumer that took a Func<string> that would read from whichever queue we’re testing and return either the string if data exists or null if not.  Then, if the item doesn’t exist, it will do a 10 ms wait before testing again.  Once all the producers are done and join the main thread, a flag will be set in each of the consumers to tell them once the queue is empty they can shut down since no other data is coming: 1: internal class Consumer 2: { 3: public Func<string> ConsumeDelegate { get; set; } 4: public bool HaltWhenEmpty { get; set; } 5: 6: public void Consume() 7: { 8: bool processing = true; 9: 10: while (processing) 11: { 12: string result = ConsumeDelegate(); 13: 14: if(result == null) 15: { 16: if (HaltWhenEmpty) 17: { 18: processing = false; 19: } 20: else 21: { 22: Thread.Sleep(TimeSpan.FromMilliseconds(10)); 23: } 24: } 25: else 26: { 27: DoWork(); // do something non-trivial so consumers lag behind a bit 28: } 29: } 30: } 31: } Okay, now that we’ve done that, we can launch threads of varying numbers using lambdas for each different method of production/consumption.  First let's look at the lambdas for a typical System.Collections.Generics.Queue with locking: 1: // lambda for putting to typical Queue with locking... 2: var productionDelegate = s => 3: { 4: lock (_mutex) 5: { 6: _mutexQueue.Enqueue(s); 7: } 8: }; 9:  10: // and lambda for typical getting from Queue with locking... 11: var consumptionDelegate = () => 12: { 13: lock (_mutex) 14: { 15: if (_mutexQueue.Count > 0) 16: { 17: return _mutexQueue.Dequeue(); 18: } 19: } 20: return null; 21: }; Nothing new or interesting here.  Just typical locks on an internal object instance.  Now let's look at using a ConcurrentQueue from the System.Collections.Concurrent library: 1: // lambda for putting to a ConcurrentQueue, notice it needs no locking! 2: var productionDelegate = s => 3: { 4: _concurrentQueue.Enqueue(s); 5: }; 6:  7: // lambda for getting from a ConcurrentQueue, once again, no locking required. 8: var consumptionDelegate = () => 9: { 10: string s; 11: return _concurrentQueue.TryDequeue(out s) ? s : null; 12: }; So I pass each of these lambdas and the number of producer and consumers threads to launch and take a look at the timing results.  Basically I’m timing from the time all threads start and begin producing/consuming to the time that all threads rejoin.  I won't bore you with the test code, basically it just launches code that creates the producers and consumers and launches them in their own threads, then waits for them all to rejoin.  The following are the timings from the start of all threads to the Join() on all threads completing.  The producers create 10,000,000 items evenly between themselves and then when all producers are done they trigger the consumers to stop once the queue is empty. These are the results in milliseconds from the ordinary Queue with locking: 1: Consumers Producers 1 2 3 Time (ms) 2: ---------- ---------- ------ ------ ------ --------- 3: 1 1 4284 5153 4226 4554.33 4: 10 10 4044 3831 5010 4295.00 5: 100 100 5497 5378 5612 5495.67 6: 1000 1000 24234 25409 27160 25601.00 And the following are the results in milliseconds from the ConcurrentQueue with no locking necessary: 1: Consumers Producers 1 2 3 Time (ms) 2: ---------- ---------- ------ ------ ------ --------- 3: 1 1 3647 3643 3718 3669.33 4: 10 10 2311 2136 2142 2196.33 5: 100 100 2480 2416 2190 2362.00 6: 1000 1000 7289 6897 7061 7082.33 Note that even though obviously 2000 threads is quite extreme, the concurrent queue actually scales really well, whereas the traditional queue with simple locking scales much more poorly. I love the new concurrent collections, they look so much simpler without littering your code with the locking logic, and they perform much better.  All in all, a great new toy to add to your arsenal of multi-threaded processing!

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