Firewall plays an important role in the protection of the server. Firewall protects the servers against harmful stuff. Firewall controls the incoming and outgoing traffic by analyzing the packet and determine whether they are allowed through or not based on set of rules. In Linux we uses IPTABLES to manage the firewall rules. But its…
The Secure Shell (ssh) protocol by default uses the port 22. Attackers mostly uses the port 22 in automated attack and changing the default will prevent your server from these automated attack. There are many ways of making your server secure and changing the default ssh port is one of the server hardening. Steps to…
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…
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…
APF(Advanced Policy Firewall) is a policy based Iptables firewall system designed for ease of use and configuration. The configuration of APF is quite simple and easy. Below are the steps to install APF firewall: 1. Change to tmp folder to download apf. cd /tmp 2. Download the apf tar file using wget. wget http://www.rfxnetworks.com/downloads/apf-current.tar.gz 3.…