Install SSH Server on Linux (Debian, Ubuntu, Fedora, CentOS, RedHat)

Debian / Ubuntu

sudo apt-get install -y openssh-server

RPM based Distros, Fedora / CentOS / RedHat

sudo dnf install -y openssh-server

or use yum

sudo yum install -y openssh-server

Start ssh service

sudo systemctl start sshd

By default the SSH service should start when the system starts, but if not try the following command to enable the service on boot up.

Debian / Ubuntu

systemctl enable ssh

Fedora, CentOS, RedHat

systemctl enable ssh

Change SSH port

Not necessary, but it is a good idea to change the default ssh port.  To change the port edit the sshd file.

vi /etc/ssh/sshd_config

How to Open a Port on Redhat, CentOS or Fedora Linux

By default iptables firewall stores its configuration at /etc/sysconfig/iptables file. You need to edit this file and add rules to open port number.

Open port 80

To open a different port just enter the port number.

Open flle /etc/sysconfig/iptables:

# vi /etc/sysconfig/iptables

Append rule as follows:

A RH-Firewall-1-INPUT -m state --state NEW -m tcp -p tcp --dport 80 -j ACCEPT

Save and close the file.  Restart iptables:

# /etc/init.d/iptables restart

or,

#service iptables restart

 

Verify that port is open

Run the following command:

netstat -tulpn | less

Make sure iptables is allowing the port you enabled:

iptables -L -n

If you need more info you can refer to the man page:

man iptables