sslh is a simple Perl script that allows you to switch incoming connection between SSH and SSL/HTTPS servers.
sslh [ -v ] [ -p [host:]port ] [ -t timeout ] [ --ssh [host:]port ] [ --ssl [host:]port ]
sslh is a simple script that lets you switch an incoming connection on a single port between distinct SSH and SSL/HTTPS servers.
sslh listens for connections on a port and is able to redirect them either to an HTTPS web server or a SSH server.
This lets one setup both a HTTPS web server and a SSH server and access them through the same host+port.
The program follows the usual GNU command line syntax, with long options starting with two dashes.
-p, --port [host:]port
The port the proxy will listen to. If no port is given, 443 is used by default. If no host is given, localhost is used by default.
-s, --ssh [host:]port
The SSH server which the SSH connections must be forwarded to. If omitted, the default is localhost:22.
-l, --ssl, --https [host:]port
The HTTPS server which the HTTPS connections must be forwarded to. If omitted, the default is localhost:443.
-t, --timeout delay
Timeout in seconds before a silent incoming connection is considered as a SSH connection. The number can be fractional.
The default is 2seconds.
Verbose output. This option can be used several times for more verbose output.
EXAMPLE OF USE
Is this tool actually useful? Yes.
For example one can use it to access both a SSH server and a secure web server via a corporate proxy that only accepts to relay connections to port 443. Creating a tunnel that passes SSH connection through a CONNECT-enabled web proxy is easy with connect-tunnel (also included in the Net::Proxy distribution).
The proxy will let both SSH and HTTPS connections out (since they all point to port 443), and the home server will connect those incoming connections to the appropriate server. This only requires to run the HTTPS server on a non standard port (not 443).
- The version adds transparent proxying so servers behind sslh see the connection as if it came from the outside, with its original IP address and port.
- It also corrects a couple of bugs which could crash sslh under heavy loads, especially in Cygwin.