[Kamailio-Users] off-topic :: empty user part of Contact header

Hello, I have a little bit off-topic question, but - may be - someone could give me an advice :-) One of our users, when replying to INVITE, sends in 200 OK Contact header without user part: SIP/2.0 200 OK CSeq: 102 INVITE Contact: <sip:1.2.3.4:1234> ... instead of: SIP/2.0 200 OK CSeq: 102 INVITE Contact: <sip:user@1.2.3.4:1234> ... and it fools our SIP<->ISUP GW and it generates completely strange R-URI in ACK :-( My questions are: 1. Is it valid Contact (without user part)? 2. What SIP<->ISUP GW should do (mirror Contact without user part to R-URI in ACK, reject/drop 200 OK etc.)? May be I can ask them to change behaviour... 3. What should do our proxy (drop 200 OK, using htable try to repair R-URI in ACK or Contact in 200 OK etc.)? 4. ??? Any suggestion is very appreciated :-) Best regards, kokoska.rokoska