sslh (applicative protocol multiplexer)

sslh accepts connections on specified ports, and forwards them further
based on tests performed on the first data packet sent by the remote
client.

Probes for HTTP, SSL, SSH, OpenVPN, tinc, XMPP are implemented.
Any other protocol that can be tested using a regular expression can
be recognised. A typical use case is to allow serving several services
on port 443 (e.g. to connect to SSH from inside a corporate firewall,
which almost never block port 443) while still serving HTTPS on that
port.

There's a tutorial on using sslh, here:

https://www.unixmen.com/sslh-a-sslssh-multiplexer-for-linux/

To start sslh as a daemon at boot, add this code to
/etc/rc.d/rc.local:

[ -x /etc/rc.d/rc.sslh ] && /etc/rc.d/rc.sslh start

Before doing this, it's advisable to have a look at the example config
files in /etc/sslh/*.cfg. The actual config file is sslh.cfg; the
others are just examples.

Optional dependencies:

libev - needed for sslh-ev executable. Most people won't need this; see
the sslh documentation for details. Will be autodetected.

libbsd - allows sslh-fork to change its process title (as shown in
'ps'), so each forked process shows what protocol and what connection
it is serving. Autodetected.