Log in from workstation to RDP server using SSH tunnel.

Workstation → Server1 > Server2 > RDP server

• Edit ~/.ssh/config

  host Server1
      hostname server1.fqdn
      user yourusername
  
  host server2
      hostname server2.fqdn
      user yourusername
      ProxyCommand ssh -q Server1 nv server2.fqdn 22

• Log in.

  ssh -L3389:RDPserver.fqdn:3389 server2

• Connect with RDP client to localhost.