KNOWLEDGE BASE

25Apr 2011

LINUX Version Info To learn the architecture and kernel version info use the shell command below: less /etc/redhat-release The output will be like CentOS release 5.6 (Final) To learn the architecture & kernel version: uname -a you can use the command above, the last numbers marked as red below is your architecture: Linux xxx.veriportal.com 2.6.18-164.9.1.el5 […]

25Apr 2011

NTP (Network Time Protocol) could be used to set time synced with ntp clocks, to do this use the shell command below: Setting time with NTP: yum install ntp -y \cp -f /usr/share/zoneinfo/Europe/Istanbul /etc/localtime ntpdate -v -b in.pool.ntp.org And set the hardware clock with: hwclock -w

23Apr 2011

You can make a search inside files within a a directory using the command “find“, to do that: with the find command cd /to_folder find . -iname ‘*conf’ | xargs grep ‘string’ -sl -iname ‘*conf’ states that the seach will only check the files ending with *conf, using -iname ‘*’ will search inside all the […]

23Apr 2011

If you own your DNS servers, you should probably want to close recursive queries being gathered from your servers. In named.conf edit the options directive and add: options { allow-transfer {Secondary Server IP; }; allow-recursion { 127.0.0.1; A.B.C/24; }; }; In secondary server: add to options: allow-transfer { none; }; allow-recursion { 127.0.0.1; A.B.C/24; };

22Apr 2011

I find Joomla non-developer friendly for the most of the time; documentation is poor and not having any continuity. I searched the net for displaying errors to the screen in Joomla 1.5 and up and here is the code: JError::raiseWarning(‘101’, “message to be displayed”); This bunch of code is especially useful if you are developing […]

22Apr 2011

If it appears to be all (***) instead of your mail hostname and if you get, “550 Sorry, your HELO/EHLO greeting must resolve (#5.7.1)” error when sending mail to your mail server from outside, run the following command in your CISCO firewall: no fixup protocol smtp 25 and save with the “wr mem” command

22Apr 2011

The standart linux distrubition calls that the ephemeral port range be between 1024 and 4999. We we all know that some of these ports are used for other more importand applications than FTP. So security is an issue because leaving those original ports open leads to major security holes. Rather than openning ports that need […]