[root@server ~]$ cat /etc/redhat-release
CentOS Linux release 6
The commands are different on other linux operating system so please check the OS before running the below commands. You can use software like putty to connect to your RHEL server through SSH. The below commands will work only on CentOS and Redhat 6 server. I have created another article for centOS 7 servers.
- Try restart using the following command: sudo service ssh restart The private/public RSA SSH keys are located in /.ssh/idrsa and /.ssh/idrsa.pub, respectively. You can transfer the public key to another machine to connect to it through public key authentication.
- Since Ubuntu 15.04, Canonical no longer ships upstart by default. Thus, the commands start, stop and restart are no longer available. The correct method for restarting the SSH service (or any other service) now is one of the two following commands: sudo systemctl restart ssh sudo service ssh restart.
- Run the command ‘service sshd restart’ to restart SSH service. Command 1: service sshd restart. Command 2: /etc/init.d/sshd restart. You can either use the command “service sshd restart” OR “/etc/init.d/sshd restart” to restart SSH service. There is no need to run both commands.
- PuTTY is a popular SSH, Telnet, and SFTP client for Windows. It is typically used for remote access to server computers over a network using the SSH protocol. This is the download page. For more information on PuTTY, see the PuTTY page. For information on SSH (Secure Shell), see the here. For information on Telnet, see here.
If you’d like SSH (or SSH and the ESXi Shell) to remain on and persist through reboots, continue to the next step. By right-clicking on a service or clicking the Actions menu item, you can adjust the policy for the service. This means you can set the service to remain on based on firewall ports or with the host and after restart.
HOW TO RESTART SSH SERVICE ON CENTOS 6 / RHEL 6 server
1 . Log into your CentOS Server as ‘root’ user2. Run the command ‘service sshd restart’ to restart SSH service
Command 1 : service sshd restart
OR
Restart Ssh Client Download
command 2 : /etc/init.d/sshd restart
You can either use the command “service sshd restart” OR “/etc/init.d/sshd restart” to restart SSH service. There is no need to run both commands.
[root@server ~]# service sshd restartStopping sshd: [ OK ]
Starting sshd: [ OK ]
[root@server ~]# /etc/init.d/sshd restart
Stopping sshd: [ OK ]
Starting sshd: [ OK ]

HOW TO STOP SSH SERVICE ON CENTOS/REDHAT 6 SERVERS
Do the below steps to stop SSH service on linux server.IMPORTANT : You might get disconnected from the server if you stop SSH service on your server. You can safely stop SSH service only if you have console access to the server.
Command to stop SSH service on centOS/RHEL linux server is given below.
1. Log into your linux server via SSH as ‘root’ user
2. Run the command ‘service sshd stop’ to stop SSH
Command 1 : /etc/init.d/sshd stop
OR
Command 2 : service sshd stop
root@server [~]# /etc/init.d/sshd stopStopping sshd: [ OK ]
OR
root@server [~]# service sshd stop
Stopping sshd: [ OK ]
HOW TO START SSH SERVICE ON CENTOS/REDHAT SERVERS
Commands to start SSH service on Linux Server is given below.Restart Ssh Client Mac
1. Log into your linux server as root user
2. Run the command ‘service sshd start’ to start SSH service
Command 1 : /etc/init.d/sshd start
OR
Command 2 : service sshd start
Restart Ssh Client Windows 10
root@server [~]# /etc/init.d/sshd startStarting sshd: [ OK ]
OR
root@server [~]# service sshd start
Starting sshd: [ OK ]
[Failed] = Means the service failed to start for some reason. Example : The service won’t start if the disk space is 100% full or if there is high load on the server. You must check the server logs to find the exact error and troubleshoot accordingly.
HOW TO CHECK THE STATUS OF SSH SERVICE
Run the command ‘service sshd status’ to check the current status of SSH service. This command will show whether SSH service is running or stopped on your linux Server.The below shows that SSH service is running fine on the server.
Command : service sshd status
OR
Command : /etc/init.d/sshd status
root@server [~]# service sshd statusopenssh-daemon (pid 14945) is running…
root@server [~]# /etc/init.d/sshd status
openssh-daemon (pid 14945) is running…
If the SSH service is down on the server it will show “openssh-daemon is stopped”
Ssh Restart Ubuntu
openssh-daemon is stopped
Restart Vsphere Web Client Ssh
If you have any webhosting control panels installed (like cPanel, plesk etc) then you can try restarting the service from frontend panel.
