Where SSH is available, this is probably the more simple and definitely more secure option

• Create admin user on the server-side (root is typically dissallowed by default)

  useradd -G wheel davidalger
  passwd davidalger
  

• Connect from the client-side via SSH

Where SSH is unavailable, use socat to start a shell when you connect from the client machine:

• From the linux console, temporarily open a tcp port

  firewall-cmd --add-port=5555/tcp --timeout=5m
  

• Start socat on server

  socat tcp-listen:5555,reuseaddr exec:bash,pty,stderr,setsid,sigint,login
  

  Note: Be aware that this will all be plaintext over the wire, so only do this on a private and secure network where MITM is not of a serious concern.

• From the client machine, connect via TCP using Serial (or if you desire to, it's possible to run socat client-side linking the shell session to a local file, which can be used with screen)