According to  <google@k9corner.com>:

    Hmm ... is that software name really spelled like that?

    [ ... ]

    I would suggest an ethernet snooping program (if you are running
OS-X, you *might* find tcpdump on the unix part hidden under the Mac
GUI, as that is the one which comes on my OpenBSD systems, and OS-X is
built on a BSD underpinning.  On Sun's Solaris, the program is "snoop",
and back on the old SunOs 4.1.x, it was "etherfind".

    Anyway -- let it run and record to a file while you are
connecting.  Ideally, limit what it records to those two systems.  And
then look at the results from that file.  That should show you which
ports are being used.  HTTP is normally port 80.  SMTP (the mail
transport protocol) is port 25.  Telnet is port 23.  "ftp" is normally
ports 20 and 21.  "ssh" is port 22.  Others which you find can often be
identified by looking in the /etc/services file.  You'll proably have to
do all of this from a terminal window, as I expect the GUI to get in
your way.  It seems to do its best to hide the unix underpinnings.

    Anyway -- you may find it attempting to use some ports which are
listed, but which make no sense based on what they carry.  Others may be
undocumented, and it may be one of these which needs to be opened.

    Good Luck,
        DoN.