[Blink] On re-invite ACK not reaching callee

[Tijmen de Mes]

Hi,

Yes all the signalling is recorded and you can see it from your account history.

We analysed it and found that in the second 200 OK, the one transmitted for the REINVITE, two record-route headers are missing. The first 200 OK on the INVITE has them. 

They should be there, but the server between the device and our proxy does not include them for some reason.

Best regards,

Tijmen de Mes
—
AG Projects.

> Op 25 aug 2026, om 13:31 heeft Robert Dyck <rob.dyck at telus.net> het volgende geschreven:
> 
> On Tuesday, August 25, 2026 12:51:51 a.m. Pacific Daylight Time Adrian Georgescu wrote:
> > Do you have the call id?
> 
> Call-ID: 84babaaa-f198-4b53-989d-98d2829946c7
> Is signaling recorded?
> >
> > > On Aug 24, 2026, at 22:46, Robert Dyck <rob.dyck at telus.net> wrote:
> > >
> > > Using latest flatpak for Linux.
> > >
> > > Caller on sip2sip.info calls subscriber at a different domain. Callee
> > > answers and dialog is established. So far all good.
> > >
> > > Caller does a re-invite ( hold ). The callee's UA sends 20OK. Caller's UA
> > > sends ACK. ACK never arrives. Callee's UA continues sending 200OK.
> > >
> > > Callee is registered as GRUU. Incoming requests are normally translated by
> > > the local registrar and the request is forwarded to the callee's IP
> > > address. This also applies to re-INVITE and its ACK. The caller learns
> > > the registrar's address from the Contact it previously received in the
> > > initial 200OK.
> > >
> > > Summary of in-dialog requests
> > > Initiial ACK - OK
> > > re-InVITE - OK
> > > second ACK - doesn't arrive
> > > Bye - doesn't arrive
> > >
> > > An important detail - Registrar/Proxy is behind NAT. Router use DMZ
> > > forwarding.
> > >
> > > The request URI of the ACK following re-INVITE is pointing at the external
> > > address of the registrar but the ACK was received at a private address.
> > > The ACK is forwarded to the external address. It never reaches the
> > > registrar because the router cannot hairpin the forwarded message.
> > >
> > > ACK
> > > sip:8 at external-address:5060;gr=urn:uuid:38ee02db-f267-4dd9-9077-1b9d4fcfb
> > > f00 SIP/2.0>
> > >                                                            Record-Route:
> > >                                                            <sip:212.95.45
> > >                                                            .179;lr;ftag=80
> > >                                                            3fbe29-6196-4af
> > >                                                            7-9771-db7d2500
> > >                                                            7e6c>
> > >                                                            Record-Route:
> > >                                                            <sip:174.142.2
> > >                                                            05.46;r2=on;lr;
> > >                                                            ftag=803fbe29-6
> > >                                                            196-4af7-9771-d
> > >                                                            b7d25007e6c>
> > >                                                            Record-Route:
> > >                                                            <sip:174.142.2
> > >                                                            05.46;transport
> > >                                                            =tcp;r2=on;lr;f
> > >                                                            tag=803fbe29-61
> > >                                                            96-4af7-9771-db
> > >                                                            7d25007e6c>
> > >                                                            Via:
> > >                                                            SIP/2.0/UDP
> > >                                                            212.95.45.179:
> > >                                                            5060;branch=z9h
> > >                                                            G4bK45c1.804d44
> > >                                                            d2.2
> > >                                                            Via:
> > >                                                            SIP/2.0/UDP
> > >                                                            174.142.205.46
> > >                                                            :5060;branch=z9
> > >                                                            hG4bK45c1.ab795
> > >                                                            fa4.2;i=d0969e0
> > >                                                            7 Via:
> > >                                                            SIP/2.0/TCP
> > >                                                            192.168.1.3:58
> > >                                                            491;received=ex
> > >                                                            ternal-address;
> > >                                                            rport=58491;bra
> > >                                                            nch=z9hG4bKPj62
> > >                                                            eb9faf-6eba-4f9
> > >                                                            1-9539-8b2954ca
> > >                                                            d94a;a>
> > > lias
> > > _______________________________________________
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> > > https://lists.ag-projects.com/mailman/listinfo/blink
> 
> 
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