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, and
any other protocol that can be tested using a regular expression, can
be recognized. 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.
Hence sslh acts as a protocol multiplexer, or a switchboard. Its name
comes from its original function to serve SSH and HTTPS on the same port.
