[Freeswitch-users] How to refuse T.38 requests

[Ali Pey]

Hello,

As you can see, the 200 OK message to the Update does not include t.38. So,
this would be a bug on your service provider if they continue to do t.38.

Almost all service providers have the ability to turn off t.38 per account.
I'd suggest you talk to your service provider.

Regards,
Ali Pey



On Fri, Dec 27, 2013 at 12:51 PM, gegetel <geo.cherchetout at laposte.net>wrote:

> Hello,
>
> My locale UAs do not know anything about T.38 protocol and I want to send a
> fax to some PSTN subscriber via OVH, my french VoIP provider, in an
> RTP/PCMA
> session. This session begins normally but, as soon as OVH's gateway
> recognizes fax tones from remote and/or locale side, an undesirable UPDATE
> with SDP for a T.38 session is sent to my side. The problem is that,
> immediately, FreeSwitch says "200 OK" instead of something like "488 Not
> acceptable here" and this is the beginning of a dialogue of the deaf which
> only takes end when remote fax-machine hangs up.
>
> I have done several things that I found in the WIKI:
>
> In my dialplan added these lines:
>
>       <action application="set" data="sip_ignore_reinvites=true"/>
>       <action application="set" data="fax_enable_t38=false"/>
>       <action application="set" data="fax_enable_t38_request=false"/>
>
> In ~/conf/vars.xml:
>
>      <X-PRE-PROCESS cmd="set" data="refuse_t38=true"/>
>
> In ~/conf/sip_profiles/external/sip.ovh.fr.xml:
>
>      <param name="t38-passthru" value="false"/>
>
> But without better result.
>
>
> This is an example of the UPDATE request:
>
> UPDATE sip:gw+sip.ovh.fr at 92.146.52.82:5080;transport=udp;gw=sip.ovh.frSIP/2.0
> Call-ID: 9686bdc8-e997-1231-27aa-001fc61584f4
> Contact: <sip:10.7.1.60:5060>
> Content-Type: application/sdp
> Cseq: 29265730 UPDATE
> From: <sip:0556ZZZZZZ at sip.ovh.fr>;tag=00-08184-01c44a83-0e1305300
> Max-Forwards: 30
> Record-Route: <sip:91.121.129.20:5060;lr>
> To: \"0033972XXXXXX\" <sip:0033972XXXXXX at sip.ovh.fr>;tag=75761tHD7541g
> Via: SIP/2.0/UDP 91.121.129.20:5060;branch=z9hG4bK-DIVG-481b17bf-03a84e77
> User-Agent: Cirpack/v4.56 (gw_sip)
> Content-Length: 299
>
> v=0
> o=cp10 138814832168 138814832170 IN IP4 10.7.1.132
> s=SIP Call
> c=IN IP4 91.121.128.144
> t=0 0
> m=image 35996 udptl t38
> a=sendrecv
> a=T38FaxVersion:0
> a=T38MaxBitRate:9600
> a=T38FaxRateManagement:TransferredTCF
> a=T38FaxMaxBuffer:1000
> a=T38FaxMaxDatagram:200
> a=T38FaxUdpEC:t38UDPRedundancy
>
> And that is the OK answer:
>
> SIP/2.0 200 OK
> Via: SIP/2.0/UDP 91.121.129.20:5060;branch=z9hG4bK-DIVG-481b17bf-03a84e77
> Record-Route: <sip:91.121.129.20:5060;lr>
> From: <sip:0556ZZZZZZ at sip.ovh.fr>;tag=00-08184-01c44a83-0e1305300
> To: \"0033972XXXXXX\" <sip:0033972XXXXXX at sip.ovh.fr>;tag=75761tHD7541g
> Call-ID: 9686bdc8-e997-1231-27aa-001fc61584f4
> Cseq: 29265730 UPDATE
> Contact: <sip:gw+sip.ovh.fr at 92.146.52.82:5080>;transport=udp;gw=sip.ovh.fr
> User-Agent:
> FreeSWITCH-mod_sofia/1.5.8b+git~20131213T181356Z~87751f9eaf~64bit
> Accept: application/sdp
> Allow: INVITE, ACK, BYE, CANCEL, OPTIONS, MESSAGE, INFO, UPDATE, REGISTER,
> REFER, NOTIFY
> Supported: timer, precondition, path, replaces
> Content-Type: application/sdp
> Content-Disposition: session
> Content-Length: 201
>
> v=0
> o=FreeSWITCH 1388128642 1388128643 IN IP4 92.146.52.82
> s=FreeSWITCH CH
> c=IN IP4 92.146.52.82
> t=0 0
> m=audio 19678 RTP/AVP 8 101 13
> a=rtpmap:101 telephone-event/8000
> a=fmtp:101 0-16
> a=ptime:20
>
> Any help much appreciated, thanks in advance...
>
>
>
>
>
>
>
> _________________________________________________________________________
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> http://www.freeswitchsolutions.com
>
> 
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