ssh (secure shell)
ssh (SSH client) is a program for logging into a remote machine and for executing commands on a remote machine. It is intended to replace rlogin and rsh, and provide secure encrypted communications between two untrusted hosts over an insecure network. X11 connections and arbitrary TCP ports can also be forwarded over the secure channel.
ssh connects and logs into the specified hostname (with optional user name). The user must prove his/her identity to the remote machine using one of several methods depending on the protocol version used (see below).
sshd (secure shell daemon) - ssh server
Install ssh on CentOS/Fedora/RHEL/Scientific Linux
Run following command in terminal
# yum install openssh-server openssh-clients
Start and stop the ssh service
# service sshd start & # service sshd stop
Automatically start the service at boot
# chkconfig sshd on
Check status of ssh
# service sshd status
Firewall :
Open Port 22 in Firewall :
Add following line in the file /etc/sysconfig/iptables
-A RH-Firewall-1-INPUT -m state --state NEW -m tcp -p tcp --dport 22 -j ACCEPT
Restart iptables
# service iptables restart
Check port 22 is opened or not
Run following command
# netstat -lnp | grep :22
Output should be like this
tcp 0 0 0.0.0.0:22 0.0.0.0:* LISTEN 9657/sshd tcp 0 0 :::22 :::* LISTEN 9657/sshd
Install ssh on Debian/Ubuntu
click here
