[OpenSIPS-Users] Add Contact header to ACK

[Vlad Paiu]

Hello,

You can use the dialog module [1] to store the Contact in a dialog 
variable, that you can append later with append_hf [2] from textops.

[1] http://www.opensips.org/html/docs/modules/1.7.x/dialog.html#id294638
[2] http://www.opensips.org/html/docs/modules/1.7.x/textops.html#id292953

Regards,

Vlad Paiu
OpenSIPS Developer


On 01/21/2012 01:29 AM, Julian Yap wrote:
> Hi,
>
> I have an issue where a T38 fax UA which is calling outbound does not
> add a contact header to an ACK when replying to the receiving party
> before starting the initial RTP conversation.
>
> As a result, the Re-INVITE from the receiving UA is misdirected and
> never gets sent to the calling UA.
>
> I'm wondering how I can add the Contact header to the ACK so that the
> Re-INVITE then sends to the right place.  I tried writing the initial
> Contact header to an AVP variable but the AVP does not persist by the
> time I get to the ACK.
>
> Below are the relevant SIP packets (changed details for privacy).
>
> === INITIAL INVITE from calling UA has a Contact header ===
>
> INVITE sip:5551234 at mysipserver SIP/2.0
> Via: SIP/2.0/UDP 8.8.8.10:5891;branch=z9hG4bK17BE
> From: IPFax<sip:1006 at mysipserver>;tag=IPF_PORT_0001_17BD
> To:<sip:5551234 at mysipserver>
> Call-ID: 9fb5d1a5-fbf7-43ee-8eed-d96a2853d91c at 10.10.0.178
> CSeq: 1 INVITE
> Max-Forwards: 70
> Contact:<sip:1006 at 8.8.8.10:5891>
> User-Agent: Net Fax/IP_FAX-9.0.6039.885
> Allow: INVITE, ACK, BYE, CANCEL, REFER, NOTIFY
> Content-Type: application/sdp
> Content-Length: 168
>
> v=0
> o=IPFax 0 0 IN IP4 8.8.8.10
> s=SIP Fax Call
> i=IPFax
> c=IN IP4 8.8.8.10
> t=0 0
> m=audio 10946 RTP/AVP 0
> a=rtpmap:0 PCMU/8000
> a=ptime:20
> a=sendrecv
>
> === ACK from calling UA does NOT have a Contact header ===
>
> ACK sip:8085551000 at 8.8.8.20:5060 SIP/2.0
> Via: SIP/2.0/UDP 8.8.8.10:5891;branch=z9hG4bK17C0
> Route:<sip:64.111.178.50;lr=on;ftag=IPF_PORT_0001_17BD>
> From: IPFax<sip:1006 at mysipserver>;tag=IPF_PORT_0001_17BD
> To:<sip:5551234 at mysipserver>;tag=IPF_PORT_0024_DE2C
> Call-ID: 9fb5d1a5-fbf7-43ee-8eed-d96a2853d91c at 10.10.0.178
> CSeq: 2 ACK
> Max-Forwards: 70
> User-Agent: Net Fax/IP_FAX-9.0.6039.885
> Proxy-Authorization: Digest
> username="1006",realm="mysipserver",nonce="4f17fa650000012ed6c5fca98a3b6522fa041bfb558d4833",opaque="",uri="sip:5551234 at mysipserver",response="b9910d8e4b5994109ec671728365b2f6"
> Content-Length: 0
>
>
> === REINVITE from receiving UA is misdirected ===
>
> INVITE sip:1006 at mysipserver SIP/2.0
> Via: SIP/2.0/UDP 8.8.8.20:5060;branch=z9hG4bKDE2D
> Route:<sip:64.111.178.50;lr=on;ftag=IPF_PORT_0001_17BD>
> From:<sip:5551234 at mysipserver>;tag=IPF_PORT_0024_DE2C
> To: IPFax<sip:1006 at mysipserver>;tag=IPF_PORT_0001_17BD
> Call-ID: 9fb5d1a5-fbf7-43ee-8eed-d96a2853d91c at 10.10.0.178
> CSeq: 3 INVITE
> Max-Forwards: 70
> Contact:<sip:8085551000 at 8.8.8.20:5060>
> User-Agent: Net Fax/IP_FAX-8.6.5262.504
> Supported: timer,replaces,billing,presence,*
> Allow: INVITE, ACK, BYE, CANCEL, REFER, NOTIFY
> Content-Type: application/sdp
> Content-Length: 359
>
> v=0
> o=IPFax 0 1 IN IP4 8.8.8.20
> s=SIP Fax Call
> i=IPFax
> c=IN IP4 8.8.8.20
> t=0 0
> m=image 49198 udptl t38
> a=T38FaxVersion:0
> a=T38MaxBitRate:14400
> a=T38FaxRateManagement:transferredTCF
> a=T38FaxMaxBuffer:200
> a=T38FaxMaxDatagram:72
> a=T38FaxFillBitRemoval:0
> a=T38FaxTranscodingMMR:0
> a=T38FaxTranscodingJBIG:0
> a=T38FaxUdpEC:t38UDPRedundancy
>
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