Bugs item #3018979, was opened at 2010-06-21 12:08 Message generated for change (Comment added) made by klaus_darilion You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=743020&aid=301897… Please note that this message will contain a full copy of the comment thread, including the initial issue submission, for this request, not just the latest update. Category: None Group: None Status: Open Resolution: None Priority: 5 Private: No Submitted By: xhu xhu (xhujohnson) Assigned to: Nobody/Anonymous (nobody) Summary: SIP UA can't receive 500(Internal Server Error) Initial Comment: SIP UA can't receive 500(Internal Server Error) after sending the REGISTER request with the equal CSeq header field value to the last value of CSeq or lower than the number. The details can be seen as follows: 1 Test topology: NUT(REG && PX) UA11 UA12 DNS | | | | IP : 3ffe:501:ffff:50::50 3ffe:501:ffff:1::1 3ffe:501:ffff:2::2 3ffe:501:ffff:4::1 aor-uri : ss.under.test.com UA11(a)under.test.com UA12(a)under.test.com contact-uri : UA11(a)node.under.test.com UA12(a)node11.under.test.com 2 tcpdump file can be seen in "SIP Registrar- REGISTER request with the equal CSeq value to or lower than the last value of CSeq" attachment 3 openser configuration file can be seen in "openser.cfg" attachment ---------------------------------------------------------------------- Date: 2010-06-21 13:07 Message: As far as I know there are some CSeq checks. But I think there is a short time intervall were the same CSeq is allowed to handle retransmissions. ---------------------------------------------------------------------- You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=743020&aid=301897…