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Old 05-05-2014, 03:13 AM
rime rime is offline
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Join Date: Dec 2011
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Default Source Port/Destination Port for SIP messages

In the trace shown, both endpoints are Session Manager systems, of different enterprises, interconnected by a SIP trunk. So it is the Session Managers which decide to use port 0 to initiate a dialogue, respectively 45561 (or other) to reply to it. The SIP entity links explicitly list TLS port 5061 for both ends of the links, on both Session Managers of both enterprises. But in reality, we see different ports in protocol traces. Building a reliable ACL is the challenge that results.
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