The number of holes that are opened in a firewall for internet telephony
is limited to a first hole used for call control and a second hole used
for audio traffic. Fixed destination ports for telephony traffic and call
control traffics are created at a destination. Media streams are received
at the telephony fixed destination port. The source of each media stream
is commanded to provide a unique identifier for each media stream
arriving at the destination from each source. Each media stream is
identified by a unique identifier provided by the source. The unique
identifier for each media stream is communicated to the destination by
each source over call control. All telephony traffic is received only at
the fixed destination port or telephony and all call control is received
only at the fixed destination port for call control.