# I'm just not gonna write troff :-) =head1 NAME sslh - ssl/ssh multiplexer =head1 SYNOPSIS sslh [ B<-t> I ] [B<-p> I] [B<-l> I] [B<-s> I] [B<-u> I] [B<-P> I] [-v] [-V] =head1 DESCRIPTION B lets one accept both HTTPS and SSH connections on the same port. It makes it possible to connect to an SSH server on port 443 (e.g. from inside a corporate firewall, which almost never block port 443) while still serving HTTPS on that port. The idea is to have B listen to the external 443 port, accept the incoming connections, work out what type of connection it is, and then fordward to the appropriate server. =head2 Protocol detection The protocol detection is made based on a small difference between SSL and SSH: an SSL client connecting to a server speaks first, whereas an SSH client expects the SSH server to speak first (announcing itself with a banner). B waits for some time for the incoming connection to send data. If it does before the timeout occurs, it is supposed to be an SSL connection. Otherwise, it is supposed to be an SSH connection. =head2 Libwrap support One drawback of B is that the B and B servers do not see the original IP address of the client anymore, as the connection is forwarded through B. B provides enough logging to circumvent that problem. However it is common to limit access to B using B or B. For this reason, B can be compiled to check SSH accesses against SSH access lists as defined in F and F. =head1 OPTIONS =over 4 =item B<-t> I Timeout before a connection is considered to be SSH. Default is 2s. =item B<-p> I Interface and port on which to listen, e.g. I, where I is the name of an interface (typically the IP address on which the Internet connection ends up). Defaults to I<0.0.0.0:443> (listen to port 443 on all available interfaces). =item B<-l> I Interface and port on which to forward SSL connection, typically I. Defaults to I (this assumes you would configure your B process to listen to port 443). Note that you can set B to listen on I and B to listen on I: this allows clients inside your network to just connect directly to B. =item B<-s> I Interface and port on which to forward SSH connection, defaults to I. =item B<-v> Increase verboseness. =item B<-V> Prints B version. =item B<-u> I Requires to run under the specified username. Defaults to I (which is not perfect -- ideally B should run under its own UID). =item B<-P> I Specifies the file in which to write the PID of the main server. Defaults to I. =back =head1 FILES =over 4 =item F Start-up script. The standard actions B, B and B are supported. =item F Server configuration. These are environement variables loaded by the start-up script and passed to B as command-line arguments. Refer to the OPTIONS section for a detailed explanation of the variables used by B. =back =head1 SEE ALSO Last version available from L, and can be tracked from L. =head1 AUTHOR Written by Yves Rutschle