Folks, There is a bug in ser, which results in different hashes to be generated if some of the fields participating in hash generation has extra spaces before value in reply that were not present in request, i.e.: request: From: <vasia_pupkin(a)1.2.3.4> reply: From: <vasia_pupkin(a)1.2.3.4> This leads to matching failure and as a result causes useless retransmition, if tm module is used. For example, Vovida's SIP stack is found to be guilty in inserting extra spaces into reply's headers (which isn't really prohibited by the RFC). Attached little patch should fix the problem. It would be nice to have it integrated into the next release. Thanks! -Maxim