you have computerA with floating ip (192.168.1.203)
you have another computerB with fixed ip (192.168.1.222)
you use ssh Reverse proxy to make other computer ssh to this computer by use this port
ssh -R 1234:localhost:22 [email protected]
so other computer can ssh to computerA by computerB's port
ssh -p 1234 computerA@A's ip
when this program launch , it would automatically set iptable rule to specific port
it would reset or drop the proxy package of client if not in whitelist