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, TLS/SSL (including SNI and ALPN), SSH, OpenVPN, tinc, XMPP, SOCKS5, are implemented, and 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.

Hence sslh acts as a protocol demultiplexer, or a switchboard. With the SNI and ALPN probe, it makes a good front-end to a virtual host farm hosted behind a single IP address.

sslh has the bells and whistles expected from a mature daemon: privilege and capabilities dropping, inetd support, systemd support, transparent proxying, chroot, logging, IPv4 and IPv6, TCP and UDP, a fork-based and a select-based model, and more.

Please refer to the install guide.

Please refer to the configuration guide.

How to use

Build docker image

make docker

docker run \
  --rm \
  -it \
  sslh:latest \
  --listen=0.0.0.0:443 \
  --ssh=hostname:22 \
  --tls=hostname:443

docker-compose example

version: "3"

services:
  sslh:
    image: sslh:latest
    hostname: sslh
    ports:
      - 443:443
    command: --listen=0.0.0.0:443 --tls=nginx:443 --openvpn=openvpn:1194
    depends_on:
      - nginx
      - openvpn

  nginx:
    image: nginx

  openvpn:
    image: openvpn

You can subscribe to the sslh mailing list here: https://lists.rutschle.net/mailman/listinfo/sslh

This mailing list should be used for discussion, feature requests, and will be the preferred channel for announcements.

Of course, check the FAQ first!