Suppose UA1, which is behind NAT, is registering a public SIP server. UA1 (only necessary headers are shown) REGISTER sip:serviceprovider.com To: <sip:[EMAIL PROTECTED]> From: <sip:[EMAIL PROTECTED]> Contact: <sip:[EMAIL PROTECTED];expires=3600>
Then UA1 receives the 200 OK response: 200 OK Contact: <sip:[EMAIL PROTECTED]:15060;expires=3600> Then UA2, which is located in other machine and is also behind NAT, registers to the same public SIP server using the same AOR. REGISTER sip:serviceprovider.com To: <sip:[EMAIL PROTECTED]> From: <sip:[EMAIL PROTECTED]> Contact: <sip:[EMAIL PROTECTED];expires=3600> Then UA2 receives the 200 OK response: 200 OK Contact: <sip:[EMAIL PROTECTED]:15060;expires=3500> Contact: <sip:[EMAIL PROTECTED]:25060;expires=3600> >From UA2 point of view, it does not know which contact header it is belong to. Another question is: would I use the contact header (with mapped public address) from the register 200 OK response to put in creating INVITE message instead of consulting the STUN server if the UA is behind NAT? Richard Senior Engineer ASTRI This message (including any attachments) is for the named addressee(s)'s use only. It may contain sensitive, confidential, private proprietary or legally privileged information intended for a specific individual and purpose, and is protected by law. If you are not the intended recipient, please immediately delete it and all copies of it from your system, destroy any hard copies of it and notify the sender. Any use, disclosure, copying, or distribution of this message and/or any attachments is strictly prohibited. _______________________________________________ Sip-implementors mailing list [email protected] https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
