In Windows Systems:
If you use a Windows System (as your Personal Computer), you can use PuTTY to connect to your Linux Server using SSH protocol.
You can download PuTTY using the link below:
http://www.chiark.greenend.org.uk/~sgtatham/putty/download.html
After running PuTTY, you need to Configuration and enter your IP address (Default SSH port is 22). Then you can login as root and enter your root password.
In Linux or Mac Systems:
You don't need and external application. Just Open Terminal and then type
ssh root@your-ip-address
to login as root. in the next step, you need to enter your root password.
