default port is 0, which then uses a port mapper so you can try this first.
ar.cfg/ar.conf is the file that holds the port i.e. TCD-Specific-Port: 4545
additionally, there is a 'register-with-port-mapper' setting...if set to true, then you don't need to specify a port when connecting, as long as you can access the port mapper, which will tell you which port it's on.
@Carl, thanks for your response and clarification