Hello,

No, that's not the case, see below the INVITE sent to the branch:

INVITE sip:123456789@1.2.3.4:5060;transport=UDP SIP/2.0
Record-Route: <sip:1.2.3.4:5060;lr;ftag=244c2803;did=cb4.8cb>
Via: SIP/2.0/UDP 1.2.3.4:5060;branch=z9hG4bK0f41.5079ae8da835958ee58ca1e8a4eb057b.0
Via: SIP/2.0/UDP 192.168.1.10:40769;received=1.3.5.7;branch=z9hG4bK-524287-1---46a5782b47b6ec85;rport=40769
Max-Forwards: 69
Contact: <sip:101@1.3.5.7:40769;transport=UDP;alias=1.3.5.7~40769~1>
To: <sip:123456789@1.2.3.4:5060>
From: <sip:101@1.2.3.4:5060;transport=UDP>;tag=244c2803
Call-ID: KfuC1GMvCvk1YCSKnHwDrw..
CSeq: 2 INVITE
Allow: INVITE, ACK, CANCEL, BYE, NOTIFY, REFER, MESSAGE, OPTIONS, INFO, SUBSCRIBE
Content-Type: application/sdp
User-Agent: Z 5.4.12 v2.10.13.2-mod
Allow-Events: presence, kpml, talk
Content-Length: 336
TOH: 123456789

v=0
o=Z 1620220570589 1 IN IP4 1.3.5.7
s=Z
c=IN IP4 1.3.5.7
t=0 0
m=audio 8000 RTP/AVP 106 9 98 101 0 8 3
a=rtpmap:106 opus/48000/2
a=fmtp:106 sprop-maxcapturerate=16000; minptime=20; useinbandfec=1
a=rtpmap:98 telephone-event/48000
a=fmtp:98 0-16
a=rtpmap:101 telephone-event/8000
a=fmtp:101 0-16
a=sendrecv

thanks

On Wed, 5 May 2021 at 16:24, Daniel-Constantin Mierla <miconda@gmail.com> wrote:

Hello,

the CANCEL to be sent is generated locally by tm module from the INVITE that was sent on the branch, so the errors is actually about a duplicate To header in that INVITE. Check it on the network to see if that's the case.

Cheers,
Daniel

On 05.05.21 16:25, Ilie Soltanici wrote:
Hello,

We are having an issue here where Kamailio is complaining about duplicate To header, while in the SIP Packet there is just one. See below the log message:

DEBUG: tm [t_msgbuilder.c:391]: build_local_reparse(): duplicate To header

ERROR: tm [t_msgbuilder.c:531]: build_local_reparse(): cannot build CANCEL request
ERROR: tm [t_cancel.c:297]: cancel_branch(): attempt to build a CANCEL failed
ERROR: tm [t_fwd.c:1434]: e2e_cancel(): cancel error

And this is the sip message:

CANCEL sip:123456789@1.2.3.4:5060 SIP/2.0
Via: SIP/2.0/UDP 192.168.1.1:19373;branch=z9hG4bK-524287-1---7774073fad1a3264;rport
Max-Forwards: 70
To: <sip:123456789@1.2.3.4:5060>
From: "101"<sip:101@1.2.3.4:5060>;tag=6f373b66
Call-ID: hC2O6zx8ZaUJ1di046
CSeq: 2 CANCEL
Proxy-Authorization: Digest username="101",realm="1.2.3.4",nonce="YJKbfWCSmlFTHxdJfKmySydF9L7FzfaqcgyOo4A=",uri="sip:123456789@1.2.3.4:5060",response="2bf2ba8ef2374d6aa8c39d650613077d",algorithm=MD5
User-Agent: TEST
Content-Length: 0

version: kamailio 5.5.0 (x86_64/linux) d4c1a1

The route itself, is like in the standard documentation:

# CANCEL processing
if KSR.is_CANCEL() :
KSR.info(RANDOM_LOG + 'KSR.is_CANCEL')
if KSR.tm.t_check_trans()>0 :
self.ksr_route_relay(msg)
return 1

def ksr_route_relay(self, msg):
if KSR.is_method_in("IBSU") :
if KSR.tm.t_is_set("branch_route")<0 :
KSR.tm.t_on_branch("ksr_branch_manage")

if KSR.is_method_in("ISU") :
if KSR.tm.t_is_set("onreply_route")<0 :
KSR.tm.t_on_reply("ksr_onreply_manage")

if KSR.is_INVITE() :
if KSR.tm.t_is_set("failure_route")<0 :
KSR.tm.t_on_failure("ksr_failure_manage")

if KSR.tm.t_relay()<0 :
KSR.sl.sl_reply_error()

return -255

Thanks
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