Siproxd is a SIP application layer proxy for
SIP-based softphones hidden behind an IP
masquerading (NAT) firewall. It includes an RTP
data stream proxy for incoming and outgoing audio
and video data. Multiple local UAs (SIP phones)
can be simultaneously masqueraded. All
configuration is done via one simple ASCII text
file. Its main purpose is to perform NAT traversal
for SIP and the RTP traffic.