How to configure routr not to rewrite request/contact during NAT traversal? #314

coffe-cafe-zed · 2025-10-14T20:12:58Z

coffe-cafe-zed
Oct 14, 2025

I'm using Routr as a SIP server with baresip clients behind NAT. When receiving incoming calls, Routr rewrites the Request-URI from the original domain to the client's public IP address, causing baresip to reject calls with "404 Not Found".

Current Behavior:

Original INVITE: INVITE sip:[email protected]:5060 SIP/2.0

Routr rewrites to: INVITE sip:[email protected]:51023 SIP/2.0

Result: Baresip responds with "404 Not Found" because it doesn't recognize 172.18.0.1:51023 as a local user

Expected Behavior:
Routr should preserve the original domain in the Request-URI so the client can properly match the incoming call to its registered account.

I have tested with:

Linphone: consistently crashes
zoiper: the only sip client that worked
baresip: can start calls but never receive/ring incoming calls

Baresip logs

10-14 22:57:08.262 15274 18700 D Baresip Lib: 22:57:08.259#
10-14 22:57:08.264 15274 18700 D Baresip Lib: UDP x.x.x.x:5060 -> 100.64.0.8:37142
10-14 22:57:08.264 15274 18700 D Baresip Lib: INVITE sip:[email protected]:47833 SIP/2.0
10-14 22:57:08.264 15274 18700 D Baresip Lib: Via: SIP/2.0/UDP 172.18.0.2:5060;rport;branch=z9hG4bK-343335-c1ba4fdbdb44a4b26aadc59978217491,SIP/2.0/UDP 100.64.0.15:48247;bra
10-14 22:57:08.264 15274 18700 D Baresip Lib: nch=z9hG4bKa7486b789599d58b;received=172.18.0.1;rport=55939
10-14 22:57:08.264 15274 18700 D Baresip Lib: Record-Route: <sip:[r.mydomain.com:5060]:5060;lr;transport=
10-14 22:57:08.264 15274 18700 D Baresip Lib: udp>
10-14 22:57:08.264 15274 18700 D Baresip Lib: Max-Forwards: 69
10-14 22:57:08.264 15274 18700 D Baresip Lib: Call-ID: f5bfbcc4099d0cda
10-14 22:57:08.264 15274 18700 D Baresip Lib: From: "1002" <sip:[email protected]:5060>;tag=77d95c32a5db1f07
10-14 22:57:08.264 15274 18700 D Baresip Lib: To:
10-14 22:57:08.264 15274 18700 D Baresip Lib:  <sip:[email protected]:5060;user=phone>
10-14 22:57:08.264 15274 18700 D Baresip Lib: Contact: <sip:[email protected]:48247>
10-14 22:57:08.264 15274 18700 D Baresip Lib: CSeq: 27267 INVITE
10-14 22:57:08.264 15274 18700 D Baresip Lib: U
10-14 22:57:08.264 15274 18700 D Baresip Lib: ser-Agent: baresip v69.2.1 (Android 15/aarch64)
10-14 22:57:08.264 15274 18700 D Baresip Lib: Allow: INVITE,ACK,BYE,CANCEL,OPTIONS,NOTIFY,INFO,MESSAGE,UPDATE,REFER
10-14 22:57:08.264 15274 18700 D Baresip Lib: Support
10-14 22:57:08.264 15274 18700 D Baresip Lib: ed: gruu,replaces,norefersub
10-14 22:57:08.264 15274 18700 D Baresip Lib: Content-Type: application/sdp
10-14 22:57:08.264 15274 18700 D Baresip Lib: X-Call-Direction: agent-to-agent
10-14 22:57:08.264 15274 18700 D Baresip Lib: Content-Length: 487
10-14 22:57:08.264 15274 18700 D Baresip Lib: 
10-14 22:57:08.264 15274 18700 D Baresip Lib: v=0
10-14 22:57:08.264 15274 18700 D Baresip Lib: o=- 
10-14 22:57:08.264 15274 18700 D Baresip Lib: 776337505 1492763144 IN IP4 100.64.0.15
10-14 22:57:08.264 15274 18700 D Baresip Lib: s=-
10-14 22:57:08.264 15274 18700 D Baresip Lib: c=IN IP4 100.64.0.15
10-14 22:57:08.264 15274 18700 D Baresip Lib: t=0 0
10-14 22:57:08.264 15274 18700 D Baresip Lib: m=audio 3706 RTP/AVP 96 9 101
10-14 22:57:08.264 15274 18700 D Baresip Lib: c=IN IP4 84.46.250.16
10-14 22:57:08.265 15274 18700 D Baresip Lib: 0
10-14 22:57:08.265 15274 18700 D Baresip Lib: a=rtpmap:96 opus/48000/2
10-14 22:57:08.265 15274 18700 D Baresip Lib: a=fmtp:96 stereo=0;sprop-stereo=0;maxaveragebitrate=28000;cbr=0;useinbandfec=1
10-14 22:57:08.265 15274 18700 D Baresip Lib: a=rtpmap:9 G722/80
10-14 22:57:08.265 15274 18700 D Baresip Lib: 00
10-14 22:57:08.265 15274 18700 D Baresip Lib: a=rtpmap:101 telephone-event/8000
10-14 22:57:08.265 15274 18700 D Baresip Lib: a=fmtp:101 0-15
10-14 22:57:08.265 15274 18700 D Baresip Lib: a=rtcp:3707 IN IP4 x.x.x.x
10-14 22:57:08.265 15274 18700 D Baresip Lib: a=sendrecv
10-14 22:57:08.265 15274 18700 D Baresip Lib: a=rtcp-rsize
10-14 22:57:08.265 15274 18700 D Baresip Lib: a=ssrc:3750
10-14 22:57:08.265 15274 18700 D Baresip Lib: 269487 cname:sip:[email protected]:5060
10-14 22:57:08.265 15274 18700 D Baresip Lib: a=mid:0
10-14 22:57:08.265 15274 18700 D Baresip Lib: a=minptime:20
10-14 22:57:08.265 15274 18700 D Baresip Lib: a=ptime:20
10-14 22:57:08.265 15274 18700 D Baresip Lib: a=label:1
10-14 22:57:08.265 15274 18700 D Baresip Lib: 
10-14 22:57:08.265 15274 18700 D Baresip Lib: ua: sipsess connect via U
10-14 22:57:08.265 15274 18700 D Baresip Lib: DP x.x.x.x:5060 --> 100.64.0.8:37142
10-14 22:57:08.265 15274 18700 D Baresip Lib: ua: sip:[email protected]:5060: UA not found: sip:[email protected]:47833
10-14 22:57:08.277 15274 18700 D Baresip Lib: 22:57:08.277#
10-14 22:57:08.277 15274 18700 D Baresip Lib: UDP 100.64.0.8:37142 -> x.x.x.x:5060
10-14 22:57:08.278 15274 18700 D Baresip Lib: SIP/2.0 404 Not Found
10-14 22:57:08.278 15274 18700 D Baresip Lib: Via: SIP/2.0/UDP 172.18.0.2:5060;branch=z9hG4bK-343335-c1ba4fdbdb44a4b26aadc59978217491;rport=5060;received=x.x.x.x
10-14 22:57:08.278 15274 18700 D Baresip Lib: Via: SIP/2.0/UDP 100.64.0.15:48247;branch=z9hG4bKa7486b789599d58b;received=172.18.0.1;rport=55939
10-14 22:57:08.278 15274 18700 D Baresip Lib: Call-ID: f5bfbcc4099d0cda
10-14 22:57:08.278 15274 18700 D Baresip Lib: From: "1002" <sip:[email protected]:5060>;tag=77d95c32a5db1f07
10-14 22:57:08.278 15274 18700 D Baresip Lib: To: <sip:[email protected]:5060;user=phone>;tag=6977653a4d692712
10-14 22:57:08.278 15274 18700 D Baresip Lib: CSeq: 27267 INVITE
10-14 22:57:08.279 15274 18700 D Baresip Lib: Server: baresip v69.2.1 (Android 13/aarch64)
10-14 22:57:08.279 15274 18700 D Baresip Lib: Content-Length: 0
10-14 22:57:08.279 15274 18700 D Baresip Lib: 
10-14 22:57:08.279 15274 18700 D Baresip Lib: 
10-14 22:57:08.392 15274 18700 D Baresip Lib: 22:57:08.392#
10-14 22:57:08.393 15274 18700 D Baresip Lib: UDP x.x.x.x:5060 -> 100.64.0.8:37142
10-14 22:57:08.393 15274 18700 D Baresip Lib: ACK sip:[email protected]:47833 SIP/2.0
10-14 22:57:08.393 15274 18700 D Baresip Lib: Call-ID: f5bfbcc4099d0cda
10-14 22:57:08.393 15274 18700 D Baresip Lib: Max-Forwards: 69
10-14 22:57:08.393 15274 18700 D Baresip Lib: From: "1002" <sip:[email protected]
10-14 22:57:08.393 15274 18700 D Baresip Lib: g:5060>;tag=77d95c32a5db1f07
10-14 22:57:08.393 15274 18700 D Baresip Lib: To: <sip:[email protected]:5060;user=phone>;tag=6977653a4d692712
10-14 22:57:08.393 15274 18700 D Baresip Lib: Via: SIP/2.0/UDP 172.1
10-14 22:57:08.393 15274 18700 D Baresip Lib: 8.0.2:5060;rport;branch=z9hG4bK-343335-c1ba4fdbdb44a4b26aadc59978217491
10-14 22:57:08.393 15274 18700 D Baresip Lib: CSeq: 27267 ACK
10-14 22:57:08.393 15274 18700 D Baresip Lib: Content-Length: 0
10-14 22:57:08.393 15274 18700 D Baresip Lib: 
10-14 22:57:08.393 15274 18700 D Baresip Lib:

coffe-cafe-zed · 2025-10-15T10:09:58Z

coffe-cafe-zed
Oct 15, 2025
Author

@psanders can you please refer some docs that can help with the above issue? Thanks

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How to configure routr not to rewrite request/contact during NAT traversal? #314

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How to configure routr not to rewrite request/contact during NAT traversal? #314

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coffe-cafe-zed Oct 15, 2025 Author

coffe-cafe-zed
Oct 14, 2025

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Oct 15, 2025
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