ssh -L 9898:firewalled.service.com:443 user@some-server

$nmap -T4 localhost
| PORT     | STATE | SERVICE   |
| 6666/tcp | open | irc        |
| 7777/tcp | open | cbt        |
| 8080/tcp | open | http-proxy |
| 9876/tcp | open | sd         |
| 9898/tcp | open | monkeycom  |
| 9999/tcp | open | abyss      |

nc -z localhost 9999
Connection to localhost port 9999 [tcp/distinct] succeeded!