Normally when we try to unmount a partition or a disk (Cd-rom or any other partitions) in Linux, sometimes we get an error umount: /xxx: device is busy. This is because other resources of the machine are still accessing the drive. You can use the fuser command to kill forcefully mounted partition or you can…
SMTP uses port 25 as its default port. When you configure mail server on your server, port 25 is use to send mails. Sometimes ISP blocked the 25 port for junk mail protection as a result you are unable to send mails from your server. Most the ISP suggests to change the Default SMTP port…
Search is the most important factor which we often used in our daily routine. Some time we need to search multiple words or string in a file, and grep provides the functionality to look into a file and search more than one words. With the combination of grep command and regular expression we can search…
Selinux is an acronym for Security-enhanced Linux. SELinux is a Linux feature that provides the mechanism for supporting access control security policies in the Linux kernel. It is a set of kernel modifications and user-space tools. To disable SELinux temporarily run the following command on shell. $ sudo echo 0 > /selinux/enforce or you can…
APF is highly powered firewall which helps you in defining Iptable rules on your server. If you are sure to remove the APF from your system, below are the steps: Remove APF # /etc/init.d/apf stop # chkconfig apf off # rm -rf /etc/apf # rm -f /etc/rc.d/init.d/apf # rm -f /etc/logrotate.d/apf # rm -f /etc/cron.daily/apf…