sslh -- A ssl/ssh 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, 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, a select-based
model, and yet another based on libev for larger
installations.

Install
=======

Please refer to the [install guide](doc/INSTALL.md).


Configuration
=============

Please refer to the [configuration guide](doc/config.md).

Transparent proxying allows the target server to see the
original client IP address, i.e. `sslh` becomes invisible.
This makes it easier to use the server's logs, and potential
IP-based banning ability.

Configuration of transparent proxying is highly dependent on
your network environment and infrastructure setup. There is
no known generic approach, and if you do not find directions
for your exact setup, you will probably need an extensive
knowledge of network management and iptables setup".

It is described in its own [document](doc/tproxy.md).


Docker image
------------

How to use

---


```bash
docker run \
  --cap-add CAP_NET_RAW \
  --cap-add CAP_NET_BIND_SERVICE \
  --rm \
  -it \
  ghcr.io/yrutschle/sslh:latest \
  --foreground \
  --listen=0.0.0.0:443 \
  --ssh=hostname:22 \
  --tls=hostname:443
```

docker-compose example

```yaml
version: "3"

services:
  sslh:
    image: ghcr.io/yrutschle/sslh:latest
    hostname: sslh
    ports:
      - 443:443
    command: --foreground --listen=0.0.0.0:443 --tls=nginx:443 --openvpn=openvpn:1194
    depends_on:
      - nginx
      - openvpn

  nginx:
    image: nginx

  openvpn:
    image: openvpn
```

Transparent mode 1: using sslh container for networking

_Note: For transparent mode to work, the sslh container must be able to reach your services via **localhost**_
```yaml
version: "3"

services:
  sslh:
    build: https://github.com/yrutschle/sslh.git
    container_name: sslh
    environment:
      - TZ=${TZ}
    cap_add:
      - NET_ADMIN
      - NET_RAW
      - NET_BIND_SERVICE
    sysctls:
      - net.ipv4.conf.default.route_localnet=1
      - net.ipv4.conf.all.route_localnet=1
    command: --transparent --foreground --listen=0.0.0.0:443 --tls=localhost:8443 --openvpn=localhost:1194
    ports:
      - 443:443 #sslh

      - 80:80 #nginx
      - 8443:8443 #nginx

      - 1194:1194 #openvpn
    extra_hosts:
      - localbox:host-gateway
    restart: unless-stopped

  nginx:
    image: nginx:latest
    .....
    network_mode: service:sslh #set nginx container to use sslh networking.
    # ^^^ This is required. This makes nginx reachable by sslh via localhost
  
  openvpn:
    image: openvpn:latest
    .....
    network_mode: service:sslh #set openvpn container to use sslh networking
```

Transparent mode 2: using host networking

```yaml
version: "3"

services:
  sslh:
    build: https://github.com/yrutschle/sslh.git
    container_name: sslh
    environment:
      - TZ=${TZ}
    cap_add:
      - NET_ADMIN
      - NET_RAW
      - NET_BIND_SERVICE
    # must be set manually
    #sysctls:
    #  - net.ipv4.conf.default.route_localnet=1
    #  - net.ipv4.conf.all.route_localnet=1
    command: --transparent --foreground --listen=0.0.0.0:443 --tls=localhost:8443 --openvpn=localhost:1194
    network_mode: host
    restart: unless-stopped
  
  nginx:
    image: nginx:latest
    .....
    ports:
      - 8443:8443 # bind to docker host on port 8443

  openvpn:
    image: openvpn:latest
    .....
    ports:
      - 1194:1194 # bind to docker host on port 1194
```

Comments? Questions?
====================

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](doc/FAQ.md) first!