|<B>-pB>, <B>--portB> [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.|
|<B>-sB>, <B>--sshB> [host:]port||The SSH server which the SSH connections must be forwarded to. If omitted, the default is localhost:22.|
|<B>-lB>, <B>--sslB>, <B>--httpsB> [host:]port||The HTTPS server which the HTTPS connections must be forwarded to. If omitted, the default is localhost:443.|
|<B>-tB>, <B>--timeoutB> delay||
Timeout in seconds before a silent incoming connection is considered
as a SSH connection. The number can be fractional.
The default is 2seconds.
|<B>-vB>, <B>--verboseB>||Verbose output. This option can be used several times for more verbose output.|
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 <B>connect-tunnelB> (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).
How can this proxy find out what kind of protocol is using a TCP connection to port 443, without being connected (yet) to the server? We actually rely on a slight difference between the SSL and SSH protocols (found thanks to <B>etherealB>):
This means that <B>sslhB> can be used with any pair of protocols/services that share this property (the client speaks first for one and the server speaks first for the other).
SSH Once the TCP connection is established, the server speaks first, presenting itself by saying something like:
SSH-2.0-OpenSSH_3.6.1p2 Debian 1:3.6.1p2-1
SSL With SSL, its always the client that speaks first.
Original idea and C version Fre\k:'|\n:uric Ple\k:'<firstname.lastname@example.org>. Perl versions Philippe BooK Bruhat <email@example.com>.
Version 0.01 of the script was a quick hack designed in 2003 as a proof of concept.
Version 0.03 correctly initialised the in connector.
Version 0.04 lets the proxy listen on any address (instead of localhost, which is still the default). Thanks to Dieter Voegtli for spotting this.
Copyright 2003-2008, Philippe Bruhat. All rights reserved.
This module is free software; you can redistribute it or modify it under the same terms as Perl itself.
|perl v5.20.3||SSLH (1)||2014-11-02|