Hi Klaus, Thx for your suggestion. The workaround is working fine with Pseudo-Variable $rb instead of $mb ("$var(sdp) = $(rb{s.striptail,2});") However, the broken body is generated by Kamailio with the filter_body() function. The server receives a multipart/mixed body and is filtering the SDP part of it with following config (excerpt): if (has_body("multipart/mixed")) { if (filter_body("application/sdp")) { remove_hf("Mime-Version"); remove_hf("Content-Type"); append_hf("Content-Type: application/sdp\r\n") } } After filtering the SDP message, the message body terminates with double CRLF, which was "space" between the individual parts / to the uniqueBoundary. I tried before using "subst" with kamailio-like parameters for removing the blank line: if (subst('/(a=[a-z]+:.+)[\r\n]{4}$/\1\r\n/s')) { and was wondering, why this does not work. The "search_body()" function accepted the match pattern and so it could not be wrong at all: if (search_body("a=[a-z]+:.+[\r\n]{4}$")) { Should this work with Kamailio? Regards, Klaus P.S. the body of the original SIP message looks as follows: [...] Content-Type: multipart/mixed;boundary=uniqueBoundary Mime-Version: 1.0 Content-Length: <length --uniqueBoundary Content-Type: application/sdp Content-Disposition: session;handling=required v=0 o=CiscoSystemsSIP-GW-UserAgent 9550 3496 IN IP4 10.16.48.44 s=SIP Call c=IN IP4 10.16.48.44 t=0 0 m=audio 16386 RTP/AVP 8 19 c=IN IP4 10.16.48.44 a=rtpmap:8 PCMA/8000 a=rtpmap:19 CN/8000 a=ptime:20 --uniqueBoundary Content-Type: application/x-q931 Content-Disposition: signal;handling=optional Content-Length: 48 0802037C052104030010231803210303 6C0C2103313730343530353335317D02 11017E0D0A2E0D0765007322143504 --uniqueBoundary Content-Type: application/gtd Content-Disposition: signal;handling=optional IAM, PRN,isdn*,,NET5*, USI,rate,c,s,c,1 USI,lay1,alaw TMR,00 CGN,04,,1,y,4,1704505351 UUS,0,1d4275050014804185000031362a640062f21001f62fbf CPC,09 FCI,,,,,,,y, GCI,67f9f408a73011e280056c205642ae68 --uniqueBoundary -------- Original-Nachricht -------- Betreff: Re: [SR-Users] 'subst' request for message body (SDP) Datum: Fri, 05 Jul 2013 17:01:56 +0200 Von: Klaus Darilion <klaus.mailinglists@pernau.at><mailto:klaus.mailinglists@pernau.at An: Kamailio (SER) - Users Mailing List <sr-users@lists.sip-router.org><mailto:sr-users@lists.sip-router.org Kopie (CC): Klaus Feichtinger <klaus.lists@inode.at><mailto:klaus.lists@inode.at Is this broken body generated by Kamailio, or by some other entity? If it is done by Kamailio with filter_body(), it should be fixed. If done by some other entity, it should be fixed in the broken entity. I have no idea why subst does not work, but as workaround you can try something like: $var(sdp) = $(mb{s.striptail,2}); set_body("$var(sdp)", "application/sdp"); regards Klaus On 05.07.2013 13:05, Klaus Feichtinger wrote: > sr-users@lists.sip-router.org<mailto:sr-users@lists.sip-router.org