In case your FW policy forbids SSH access to the DMZ or internal
network from outside, but you still want to use ssh on machines
which only have one open port, e.g. HTTP, you can use sshttpd.

Sshttpd can multiplex the following protocol pairs:

* SSH/HTTP
* SSH/HTTPS
* SSH/SMTP (without SMTP multiline banners)
* HTTPS SNI multiplexing
* SSH/HTTPS with SNI multiplexing