Tutorial Category

Troubleshooting

  1. BGP for IPv6 - iBGP Full Mesh

    By Algert Gjeka tagged in BGP,BGP for IPv6,debug,Full Mesh,iBGP,IPv6,Router
    Introduction to BGP IPv6 In this tutorial I will be configuring the BGP for IPv6 router iBGP Full Mesh.  I will start off with the baseline show command, “show BGP IPv6, unicast summary” to display general information about IPv6 BGP neighbors. Then I am going to enable a debug command “debug BGP IPv6 unicast” to see how things unfold as I configure the BGP for IPv6 router iBGP Full Mesh. Finish with the same baseline command, “show BGP IPv6 unicast summary” to see what changed. Let’s look at the network topology. I will be configuring the BGP...
  2. How To Flush Linux / UNIX DNS Cache

    I'm on a Dial UP Internet connection under Linux and frequent dial up disconnection causing dns problems. How do I flush DNS cache under UNIX / Linux distribution using a shell prompt? Under MS-Windows you can use the ipconfig command to flush dns cache. However, Linux and UNIX provides various ways to flush cache. Linux can run nscd or BIND or dnsmasq as the name service caching daemon. Large and work-group servers may use BIND or dnsmasq as a dedicated caching server to...
  3. URL File-Access Is Disabled Error After Upgrading To PHP 5.2

    If you have recently upgraded to PHP 5.2.x or newer and are getting an error on your site saying URL file-access is disabled in the server configuration, you may be affected by a new PHP configuration change. As of PHP 5.2.0, a new configuration directive, allow_url_include, was introduced in an effort to enhance security in file inclusion. The introduction of this directive allows an admin to keep allow_url_fopen enabled for scripts that need it, but disable remote includes for include() and require() functions. Note: We should...
  4. How To Test DNS Resolution With NSlookup

    What is NSlookup? NSlookup is a utility that allows users to verify that a given domain name (or domain record) is resolving properly locally on their PC. It is also useful to check DNS caching, to ensure that after a DNS changeover that the PC is seeing the new IP address entry. Using NSlookup To access nslookup on a Windows workstation, perform one of the following: Windows 7 or Vista: From the Start menu, in the search field, type cmd, and then press Enter. ...
  5. How To Test Connectivity With Traceroute

    What is Traceroute? The traceroute utility checks how many “hops” (transfers through other routers or networked devices) it takes for your computer to reach a destination. You can use traceroute if you know the other computer's IP address, web site address, or name (e.g., 1.1.1.1, www.BIPmedia.com, etc). Using Traceroute To access traceroute on a Windows workstation, perform one of the following: Windows 7 or Vista: From the Start menu, in the search field, type cmd, and then press Enter. Previous versions: From the Start menu, select Run… . In the “Open:”...
  6. How To Test Connectivity With Ping

    These tests are performed using a Windows workstation. If you have a MAC or a *nix PC, the instructions will be a little different (details to be added soon). Running a Ping Ping is one of the first tools to use to point to point connectivity. It's run through the command prompt, but getting the basic information is quite easy: To run ping, type Start > Run. Type cmd in the Run window, and click OK. A black and white command line window pops up. Type ping followed by an IP...
  7. ImageMagick [Imagick] PHP Class Broken Or Fails To Install

    Introduction to Imagick Some versions of CentOS (including the most recent 5.5) have an issue with a buggy 6.4.8 RPM version of ImageMagick. This version prevents the Imagick PHP class from working properly, and also prevents the extension from being installed via PECL. If you are using this PHP class on your site, you will see an error something like: Fatal error: Class 'Imagick' not found in /home/user/public_html/file.php on line 92 When trying to install via PECL, the error will be: ...
  8. How To Fix A Crontab Wrong Permission Error

    By Tasia tagged in cron,file system permissions,how-to
    If you are receiving the error /usr/bin/crontab permissions are wrong. Please set to 4755 when in the cron section of cPanel, the commands below may correct the error for Redhat/CentOS/Fedora servers. Log into the server via SSH or the console as root and run: yum -y install vixie-cron crontabs chmod 4755 /usr/bin/crontab That's it. See how easy it is to fix permission errors in your crontab. Feel free to leave me a reply below if you have any question or needs my help. ...