Setting up Forwarding IP VS on LTM to route SSH traffic

If not using SNAT the internal server would need to use BIG-IP as the gateway so you would get an open session and never get the SSH server response after ack. But.... depending on what version you have, this may benefit you if you haven't already gone over it.

https://support.f5.com/kb/en-us/products/big-ip-afm/manuals/product/network-firewall-policies-implementations-12-1-0/13.print.html