• nfs tuning maximum amount of connections


    By default at least on Centos 7 nfs only allows 8 connections and starts 8 nfsd daemons. To fix this edit this file:/etc/sysconfig/nfs Edit the line "RPCNFSDCOUNT" (uncomment it so it looks like this: RPCNFSDCOUNT=30 In the example above we are setting 30 nfsd daemons to run (or in other words 30 connections are possible this way).........
  • Debian Ubuntu Mint Howto Create Bridge (br0)


    Having a network bridge allows you to bridge traffic under multiple devices so they can talk natively without using any special routing, iptables/firewall or other trickery. To create your bridge you need the bridge-utils package for brctl and if you want to do things like bridge VMs that run on a tap device you will need the uml-utilities which provides "tunctl". Install the utilities to make our bridge sudo apt-get install........
  • Linux delete unused tap devices automatically


    This will find all tap devices and try deleting all of them. Of course don't run this if there is a chance an unused tap device is necessary and would not be created by the script ro application using it. for tap in `ifconfig -a|grep tap[0-255]|awk '{print $1}'`; do tunctl -d $tap done........
  • Debian / Mint / Ubuntu net-tools packages provides netstat, ifconfig, route, arp and other classic network admin tools


    The net-tools command brings back all of the oldschool tools that we're used to: /bin/netstat /sbin/ifconfig /sbin/ipmaddr /sbin/iptunnel /sbin/mii-tool /sbin/nameif /sbin/plipconfig /sbin/rarp........
  • ssh reverse proxy to enable remote access behind a LAN and firewall


    So say you are behind a typical NAT/LAN setup whether at home, work or while travelling. What if you have a computer or server that you need to connect to from the outside? Yes you could use a VPN but a quick and dirty, temporary and secure way is to use SSH's Reverse Tunneling Proxy feature. Requirements On the remote ssh server host you need the GatewayPorts option enabled in sshd_config (be........
  • OpenVPN error ERROR: Cannot ioctl TUNSETIFF tun: Operation not permitted (errno=1)


    This basically means that you are running as non-root and you need to be root to create the tun0 or tap0 device on OpenVPN. You could try sudo or adding the openvpn binary to the list of sudoers.........
  • OpenVPN cannot ping remote IP routing loop issue after connecting


    Sometimes if you have a very basic configuration OpenVPN on the client side for some reason sends all traffic to the OpenVPN server IP through the tun0 which is of course impossible and creates a block or routing loop. This is because you need to use your normal ISP/LANgateway to hit the OpenVPN server if it is remote/offsite as is usually the case. So if you are connected to the OpenVPN through say a tun0 device and your routing is set to connect to the OpenVPN&nbs........
  • Linux Mint Ubuntu Debian How To Disable Webcam Automatically Onboot To Prevent Spying and Privacy Violations


    It is well known hackers, the NSA, CIA and other groups have created malware to secretly turn on your webcam and microphone on your phone, tv etc.. But fortunately on our computers and laptops we have some options. Most webcams use the "uvcvideo" kernel module / driver. You can disable this in two ways on boot. I recommend both just as a failsafe. Disable it on rc.local once your system boots automatically Add the followi........
  • h264 DVR security camera footage cannot be played


    This is not just a Linux issue but a general issue most software or hardware players cannot play the resulting exported/backed up format of .h264 from DVR security camera footage for some silly reason. There is a simple solution in Linux using ffmpeg fortunately. Convert the .h264 file into mp4 ffmpeg -i yourfile.h264 -codec copy video.mp4 play dvr .h264 file........
  • FreeBSD/OpenBSD OpenVPN Client error "Cannot allocate TUN/TAP dev dynamically"


    I have never had this error on Linux and this is running FreeBSD as root: Wed Aug 9 04:29:34 2017 us=329050 Cannot allocate TUN/TAP dev dynamically Wed Aug 9 04:29:34 2017 us=329832 Exiting due to fatal error The Solution you need a kernel module that is for some reason not automatically loaded like Linux: kldload if_tap........
  • Cannot allocate TUN/TAP dev dynamically - FreeBSD/OpenBSD OpenVPN Client error Solution


    I have never had this error on Linux and this is running FreeBSD as root: Wed Aug 9 04:29:34 2017 us=329050 Cannot allocate TUN/TAP dev dynamically Wed Aug 9 04:29:34 2017 us=329832 Exiting due to fatal error The Solution You need a kernel module that is for some reason not automatically loaded like Linux: kldload if_tap........
  • OpenVZ Solution CPT ERR: c02fa000,73 :CPT: lock fd is closed incorrectly: 1 and vps-net_add ERROR: Unable to add route ip route add 192.168.5.2 dev venet0


    The only solution after trying many suggestions was to simply restart the "vz" service (definitely not preferable). Even doing an ifdown and ifup for venet0 did not help. ifup venet0 Bringing up interface venet0: Configuring interface venet0: net.ipv4.conf.venet0.send_redirects = 0 RTNETLINK answers: Network is down Some errors from log: CPT ERR: d2dc60........
  • DRBD Slow Performance - 99.99 % [jbd2/drbd0-8] highiowait solution


    Tired of checking iotop and seeing that your drbd partition is using 99.99% of io all the time and finding your drbd device performs slow in general? This is especially an issue in versions of DRBD in the 8.3 tree in particular one documented case is on "8.3.13" but it likely applies to other devices. The symptoms are that resyncing is fine and normal but any reasonable amount of activity is very slow and lagged and creates a high server load and con........
  • Linux How To Recover Partition Table from Kernel and Restore Centos/Debian etc..


    We've all done this at some point, you work on the wrong shell window and this was my first time making this mistake but I deleted a partition table in fdisk, recreated it and saved it with "wq" and even ran partprobe! If you haven't rebooted yet then you can still recover your partition table, otherwise you're in big trouble. Fortunately since it was a live system and in use the kernel still had to use the old table like below:........
  • tsclient (Terminal Server RDP Client) missing in Debian, Ubuntu, Linux Mint


    This was a horrible shock after upgrading fromUbuntu 9 to Linux Mint 17 and I found that the last distro to support tsclient was Debian Squeeze. For some reason it has disappeared for a long time and the new options such as rdesktop and gnome-rdp do not have any start menu entry and just aren't done as well as tsclient. Fortunately there is a solution: tsclient surprisingly can be downloaded as a direct .deb package and it fails with some variou........
  • Centos/obfsproxy errors


    I never did get it working, it is too bad as obfsproxy should really be an option and integrated into the OpenVPN client and server or something similar: yum -y install python-pip python-devel No package python-pip available. #install the EPEL repo python-pip install obfsproxy python-pip install obfsproxy -bash: python-pip: command not found pip install obfsproxy &........
  • Openvz Enable netadmin


    vzctl set $CTID --devnodes net/tun:rw --capability net_admin:on --save........
  • HP XW9400 Motherboard In Desktop Issues


    Fortunately the format is EATX so an EATX case will work and the screw layout is standard. You will need to remove the HEX/TORX screws that are connecting the stock HP standoffs (meant to slide into an HP case). XW9400 Motherboard Issues Size: 12" x 13" Proprietary Power Connector Proprietary CPU Power Connector Proprietary Memory Power Connector Fan connectors are 4 pin so you will need some kind of adapter.........
  • KVM/QEMU how to boot from direct kernel vmlinuz and initrd with networking


    Thsi is very handy when doing your own kernel development. -m specifies how much ram (in the example it is 768MB) -kernel specifies the path to the kernel file -net tap,ifname=tap1,script=no (the ifname=tap1 is what you need to change and setup manually). *Run "tunctl -b" to create a tap device and use the one it gives you for ifname= Enable networking to the outside like this: *Note we assume that your bridge is br0 i........
  • OpenVZ mismatched kernel and dev when compiling.


    ./configure ./configure: line 91: cd: /lib/modules/2.6.32-042stab084.25/build: No such file or directory Error: kernel version not found. Please make sure your kernel is configured. dr-xr-xr-x. 4 root root 4096 Feb 21 06:13 .. lrwxrwxrwx 1 root root 45 Feb 21 06:13 build -> ../../../usr/src/kernels/2.6.32-042stab084.25 drwxr-xr-x 2 root root 4096 Feb 12 20........
  • Sipura / Linksys PAP/VOIP/SIP Adapter Issue Can't receiving incoming phone calls and you're behind a NAT router (99% of people)? solution


    Sipura / Linksys PAP/VOIP/SIP Adapter Issue Can't receiving incoming phone calls and you're behind a NAT router (99% of people)? 1. Login to the adapter. 2. Click on "Advanced" (location varies but usually somewhere on top) 2. Click on "SIP" 3. Scroll down to "NAT" (usually at the bottom). You'll find 2 columns with 4 rows of drop-down boxes (they'........
  • Bash weird variable whitespace missing when echoing printing


    Bash weird variable whitespace missing var=`cat tlds.csv|grep .ca,` # echo "var=:$var:" :ar=:.ca,Canada Why is the v missing in the last line? It should be :var=:.ca,Canada instead of :ar=:.ca,Canada I noticed a problem with the file with doing a "cat -v" on it. Here's the issue, the file contains carat M ^M: .vg,British Virgin Island........
  • mysqldump: Couldn't execute 'show create table `general_log`': SHOW command denied to user 'user'@'localhost' for table 'general_log' (1142) - Solution


    mysqldump: Couldn't execute 'show create table `general_log`': SHOW command denied to user 'user'@'localhost' for table 'general_log' (1142) One of my clients almost found out the hard way, here is an unlikely situation that happened. 1.) Years ago the client had another VPS to which they backed up a BLOG nightly to an .sql file, what they forgot is that the file also contained all databases (they used the --all-databases option but forgot). So imagi........
  • Country List Names in HTML Select From


    This is useful for developing a lot of applications, I'm putting it here to keep it handy for myself and hopefully others: Choose CountryCanadaJapanUnited StatesUnited KingdomAfghanistan........
  • Creating tunnel gives the error ioctl: no such device


    ip tunnel add tun3 mode gre remote 192.58.1.5 ttl 64 ioctl: no such device I solved this on Centos by loading the ip_gre module: modprobe ip_gre On Debian I believe it is the "sit" module.........
  • ioctl: Operation not permitted can't delete tunnel


    When trying to delete a tunnel ip tunnel del tunl0 I get this message: ioctl: Operation not permitted........
  • HowTo Migrate and Import iPhone/Outlook Contacts into Android without using GMail using .vcf files


    I searched for days after getting my Galaxy Note and couldn't find a way to do this (at least not without buying programs for either Android/Windows). All I read was ways to sync and import the contacts to GMail but I don't want to use GMail for privacy reasons. GMail/Google steal all of your personal information and use it for whatever purposes they want to and may sell or release it to who knows where (I don't care what their policy says but this stuff happens), just like the default........
  • Asus VE247H 23.7" Inch LCD/LED Backlit Monitor Dead/Stuck Pixel Policy Complaint


    I've thought for awhile that Asus has been banking on its years old reputation for quality amongst gamers and enthusiasts and I think I'm right. My Asus VE247H Monitor with a supposed 2MS refresh rate has 1 red/stuck/dead pixel but fortunately it can only be seen on a non-true black picture or against a blue screen. I have several Asus products and find they're all of fairly poor quality. First of all their motherboards have given me the most issues of any brand, they te........
  • rpmforge: [#### ] 471/10722Segmentation fault yum[18934]: segfault at 0000000000000000 rip 00002ade62153a30 rsp 00007fff76f9fe58 error 4


    A few days ago this happened on multiple Centos 5 servers and apparently anyone using rpmforge was affected by this error and there was no solution other than disabling that repo to fix it. To some this highlighted a few points, that there is a reason RHELexists with full paid support, and also that this could be a vulnerability and huge flaw with yum. A yum search or install should not segfault just because the rpmforge repo goes down. Fortunately it came back up........
  • MYSQL Error Can't find file: './wf/Sessions.frm' (errno: 13) Solution


    mysql errors even though these files do exist: 110405 13:21:37 InnoDB: Operating system error number 13 in a file operation. InnoDB: The error means mysqld does not have the access rights to InnoDB: the directory. InnoDB: File name ./ibdata1 InnoDB: File operation call: 'open'. InnoDB: Cannot continue operation. 110405 13:26:15 InnoDB: Operating system error number 13 in a file operation. InnoDB: The error means my........
  • Openvz Enable TUN/TAP OpenVPN


    Make sure the module "tun" is loaded on the host. vzctl set 2000 --devnodes net/tun:rw --save *Note what's below is what OpenVZ says you need (but I've never had to do it) vzctl exec 2000 mkdir -p /dev/net vzctl exec 2000 mknod /dev/net/tun c 10 200 vzctl exec 2000 chmod 600 /dev/net/tun On the container test the device: when Something is wrong:........
  • Installing Webmin & Enabling SSL


    Webmin Setup Centos 5: wget http://downloads.sourceforge.net/project/webadmin/webmin/1.530/webmin-1.530-1.noarch.rpm?r=http%3A%2F%2Fwww.webmin.com%2Fstandard.html&ts=1294339690&use_mirror=surfnet [1] 24229 [2] 24230 [root@host ~]# --2011-01-06 21:48:20-- http://downloads.sourceforge.net/project/webadmin/webmin/1.530/webmin-1.530-1.noarch.rpm?r=http%3A%2F%2Fwww.webmin.com%2Fstandard.html Resolving downloads.sourceforge.net... 216.34.181.........
  • Thunderbird Signature Problem & Solution - Defaults To Below Quote


    Basically it seems that Thunderbird only remembers/savesfor the first/default identity account. It is very annoying when the signature gets placed at the bottom and another huge oversight on Mozilla's part. Fortunately you can hack/manually set this setting. The solution for fixing the Signature At the Bottom (Below The Quote) Click Tools -> Options ->Advanced -> Config Editor Then search for ".sig_bottom" and set them al........
  • FUSE/Curlftpfs mount ftp account as drive partition in Linux


    This is a great way to use your ftp server space, for example on your web hosting account (althoughI believe many hosts don't allow storage like this), but if you have a VPS/Dedicated Server etc.., this would be perfect. Imagine how easy it is to work with an ftp account that you can just mount as a normal partition or directory in Linux, it would be great for backups etc.. Name curlftpfs - mount a ftp host as a local directory Synopsis........
  • OpenVZ user_beancounters kmemsize failcnt Processes Timing Out/Doing Nothing/Zombie


    cat /proc/user_beancounters produces the following: kmemsize 1861537 5139870 12752512 12752512 26965041 Notice the failcnt "26965041", that is for kmemsize and at first it confused me. The system had enough guaranteed and enough burst RAM available. kmemsize is a variable indepedent of that, but who cars about the explanation right, let's just make thing........
  • Picking an FTPD (vsftpd) Server in Linux Centos/Debian


    I decided on using yum to help me decide even though I normaly use proftpd I decided to see what else I could find. yum search ftp Loaded plugins: fastestmirror Loading mirror speeds from cached hostfile * rpmforge: ftp-stud.fht-esslingen.de * base: mirrors.netdna.com * updates: updates.interworx.info * addons: yum.singlehop.com * extras: mirrors.netdna.com rpmforge........
  • PHP cannot access /usr/bin/openssl


    PHP cannot access /usr/bin/opensslI have verified the username that runs the process is able to access /usr/bin/openssl and it does exist but the PHP script is saying it doesn't exist: [code:1:1fd0f3abbe] if (!file_exists($OPENSSL)) { //echo "ERROR: OPENSSL $OPENSSL not foundn"; }[/code:1:1fd0f3abbe] I don't get itI can clearly see the contents of /usr/bin by using the PHP system fu........
  • Starting/Creating Services


    Starting/Creating Serviceshttp://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/configtuning-starting-services.html That might help........
  • CDR Manufacturers - Why is so much media bad?


    CDR Manufacturers - Why is so much media bad?I have searched for good media and tried many kinds for years. I guess I'll try to summarize my findings and conclusions. Dye is irrelevant, dye of any color can be good or bad, it more likely depends on the manufacturer. Speaking of manufacturers, the name at the top of the disc means nothing. For example, Memorex along with any other 'brand' is actually always made by another manufaturer including CMC Mag........
  • Adventures in pre-paid SIM Cards and data GPRS/Edge/3G in China with China Mobile in Shenzhen, Guangzhou, Shanghai, Beijing and other cities


    This really is a difficult and confusing process for non-Mandarin speakers, but here's what I've done and learned so far: You can purchase an "M-Zone" China Mobile pre-paid SIMCard from almost anywhere but I tried to purchase mine from Suning (a large electronics dealer) hoping they would be able to help me or answer my questions but my plan didn't work out at all. At Suning once I found someone who spoke some English they gave me the 55 RMB M-Zone China Mobile P........
  • iPhone Enable Tethering Manually Update ipcc Carrier Settings/Update via SSH


    Everyone says there is a "manual" way of doing it and then they tell you to use iTunes, but if you're like me, you're travelling on business in a foreign country and your laptop does not have iTunes and you don't have a way of getting it and/or don't want it. For this example I'm using the provider "du" in Dubai, UAE (United Arab Emirates) but this method works for virtually all providers. The requirements in this case to truly "manually update........
  • Unixbench Score with Glusterfs/Openvz & Quad Core Xeon - Updated with GlusterFS 2.0.8


    You might remember my original GluserFS/OpenVZ benchmark which produced a horrible 29.8 This is the exact same system, but using the latest 2.0.8 (with some small files patch which speeds up performance) you can see it is about 25% faster. I also haven't tuned my config files at all, but there are some settings that should increase performance on small files which I believe i........
  • Tyan S2735-8M Maximum Hard Drive Limit/Not Working/Doesn't work with 1TB 1000GB hard drives


    Inever saved any of the logs, but basically no matter what OS (Linux)I used, I could not get my 1000GB hard drive to work (Seagate SATA). The BIOS recognizes the drive and fdisk -l shows the hard drive as it should. The tricky thing is that different OS's will give you different results, but don't be fooled. You can't use these larger drives for long. Iwas getting all kinds of seek/IOerrors and also messages that the port could not be read.........
  • How To Save iptables firewall rules Centos/Redhat/Fedora Linux


    This is something that annoys a lot of people, fortunately the Redhat style OS's are the most simple in this respect. I disagree that Debian's way makes sense, it is more of a hackish approach in how they implement iptables. Anyway, for those who are using Redhat/Centos style OS's it is very simple. Set your rules from the shell/command prompt and to save the iptables firewall rules so they are remember/loaded on boot just run this command: service iptables........
  • iPhone/iTunes sync error "0xE8008001"


    This happened during a sync of my iPhone while installing some apps. This usually happens to non-jailbroken iPhones who are trying to install non-Apple approved software OR jailbroken phones who haven't done the "Sync update". How to fix this error and get the Sync Update Open Cydia - Manage - Sources - Edit Add this source: http://cydia.hackulo.us Then under the section "Hackulo.us" install "Ap........
  • iPhone 3GS Jailbreak Information & Benefits


    Truly, the only way to unleash the capabilities and customization abilities of iPhone are to jailbreak, it's not just for hackers anymore. A few days ago someone by the named of "geohot" released a single click application called "purplera1n", which does the entire operation smoothly and seamlessly. In our case, the first time it went as far as "done, wait for reboot" on our Windows machine and for minutes we waited and saw the pic on the iPhone w........
  • mkisofs error "genisoimage: Directories too deep for 'Backup/My Documents/My Music/iTunes/Album Artwork/Local/5928CE9C1AFAC465/07/15' (7) max is 6."


    genisoimage: Directories too deep for 'Backup/My Documents/My Music/iTunes/Album Artwork/Local/5928CE9C1AFAC465/07/15' (7) max is 6. Some people said choosing the --iso-level-4 option will help. I just opted to add the "-D" switch and everything was fine.........
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