allowing ssh in campus

[vaida bogdan <vaida.bogdan@gmail.com>]

My campus connections look like this:

Dorm1 gateway ----\
Dorm2 gateway ----|=> Campus gateway |-> OUTSIDE
Dorm3 gateway ----/                                  \-> University Servers

Dorms' ips are private on different internal networks.

I want to allow ssh (and other ports) access on request to users from
one of the Dorms to OUTSIDE.

If I allow Student1 ssh on dorm1 gateway then what do I tell the
Campus gateway to allow ? (I can't allow full access from Dorm1's
gateway public ip.

I would also like to consider security matters: (allow by ip&mac, or
through proxy).

Thanks in advance,
   Bogdan