Enabling SSH for a TrueNAS jail

Generally not a good idea from a security standpoint, but if you have a lot of CLI work to do in a FreeNAS jail, it can make life easier.

If nothing else, seeing a lot more data on the screen, and being able to copy/paste commands has it's advantages.

Steps:

1. Enable sshd:

   sysrc sshd_enable="YES"
   sshd_enable: NO -> YES
   

2. Start sshd:

   service sshd start
   

3. Add a user, and note that the new user must be a member of the wheel group in order to use the su command:

   adduser
   Username: jailuser
   Full name: Jail User
   Uid (Leave empty for default):
   Login group [jailuser]:
   Login group is jailuser. Invite jailuser into other groups? []: wheel
   Login class [default]:
   Shell (sh csh tcsh git-shell zsh rzsh nologin) [sh]: csh
   Home directory [/home/jailuser]:
   Home directory permissions (Leave empty for default):
   Use password-based authentication? [yes]:
   Use an empty password? (yes/no) [no]:
   Use a random password? (yes/no) [no]:
   Enter password:
   Enter password again:
   Lock out the account after creation? [no]:
   Username   : jailuser
   Password   : *****
   Full Name  : Jail User
   Uid        : 1002
   Class      :
   Groups     : jailuser wheel
   Home       : /home/jailuser
   Home Mode  :
   Shell      : /bin/csh
   Locked     : no
   OK? (yes/no): yes
   adduser: INFO: Successfully added (jailuser) to the user database.
   Add another user? (yes/no): no
   Goodbye!
   

4. Set the jail root password to allow users to use su:

   passwd
   Changing local password for root
   New Password:
   Retype New Password:
   

5. Once you're done, stop sshd, and disable the service, as a "best practice":

   service sshd stop
   

   sysrc sshd_enable="NO"
   ssh_enable: YES -> NO
   

Reference

FreeNAS 11.3-U5 User Guide - Accessing a jail using ssh https://www.ixsystems.com/documentation/freenas/11.3-U5/jails.html#accessing-a-jail-using-ssh