SSH is included and set up in v6, but it will only work with earlier versions if you install an SSH package.

The Telnet sections should work for all versions of unRAID, but the SSH sections are only useful for systems with SSH installed and working. Naturally, you should already have entered a password for 'root' on your unRAID server! Note: this page assumes you are running unRAID v6. Another recommendation, for Windows or Mac, is Xshell, similar to PuTTY. Instructions and links in the PuTTY section below. For Windows, PuTTY is the recommended package, with enhanced support for both Telnet and SSH. Linux and Mac stations already have terminal access built in. But please remember that it is more secure to disable Telnet, and set up SSH for all further terminal access. There are instructions below for disabling Telnet, but Telnet does make it easier the first time you want to access your server from another machine. SSH is recommended instead as more secure. Telnet is no longer recommended however, because it is older and easier to attack. For terminal access from other machines, unRAID includes both Telnet and SSH support.

If you have a monitor attached to your unRAID server, then when you boot normally (not the boot GUI), you end up at the console with a login prompt. Linux terminal sessions usually always require a login with password. It's very similar to an MS-DOS command prompt in Windows, a 'DOS box', except this is Linux, so you can't use DOS commands. It's called by different things, such as a 'shell' or 'console' or 'terminal' or 'command window', but always is line driven and has a command prompt. Terminal Access What is 'Terminal access'? Synonyms for 'terminal': console, shell, command window, DOS box, command prompt, Windows cmd shell, Telnet window It's the opening of a terminal session and obtaining a command line prompt, at which you can enter commands directly on the system, whether you are on the system itself using its keyboard and monitor, or on a different machine using SSH or Telnet. 1.4 Opening a terminal session with the Windows Telnet tool.

Mac terminal commands wiki