Hi guys, I've been searching through the forum by couldn't find any similar issue. I have configured VoIP provider in 3cx. Registration is not required, IP for Contact header is set to Internal. Everything works fine for both incoming and outgoing calls. However, in Wireshark traces, I can see that 3cx puts 0.0.0.0 into it's contact header for incoming calls. This is clearly non-compliant with RFC3261, and I'm lucky that my VoIP provider doesn't care about this non-compliance. But I might need to connect to other VoIP providers, that are much more serious about RFC3261 compliance. Did anybody experience same behavior?