PIAF2: T.38 Faxing

[atsak]

I want to try to get T.38 working on PIAF 2.0.6.1, or put another way on Asterisk 1.8.8.0 with an SPA2102. Currently the faxes fail on negotiation every time.

I have it working on inbound faxes in PIAF 1755 on Asterisk 1.4, but the same settings don't work on PIAF 2.0.6.1

I've added t38pt_udptl=yes,redundancy (and tried without redundancy) in sip_general_custom.conf, and set the SPA using the suggestions in this thread:

freepbx.org/forum/freepbx/users/activating-t38-passtrough-in-freepbx

I see the force t38 being sent by the SPA2102 (in the debug output from the SPA) then the SIP debug on the Asterisk server shows 488 Not Available Here (please ask if you'd like to see more SIP debug output, I think this is the only relevant info).

[2011-12-28 14:54:49] VERBOSE[1849] chan_sip.c:
<--- Reliably Transmitting (no NAT) to 10.1.3.194:5060 --->
SIP/2.0 488 Not acceptable here
Via: SIP/2.0/UDP 10.1.3.194:5060;branch=z9hG4bK-890abb0c;received=10.1.3.194
From: <sip:[email protected]>;tag=2784d7d291356100i0
To: "(N/A)" <sip:[email protected]>;tag=as469d8518
Call-ID: [email protected]:5060
CSeq: 101 INVITE
Server: FPBX-2.8.1(1.8.8.0)
Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, SUBSCRIBE, NOTIFY, INFO, PUBLISH
Supported: replaces, timer
X-Asterisk-HangupCause: Normal Clearing

I do appreciate that fax is the bane of all our existence but I really need to operate a few analog faxes through our existing infrastructure and would be greatly appreciative of any pointers someone might be able to offer.

 

[jroper]

Hi

Can you try a test with the firewall switched off?

Joe

 

[atsak]

I like your thinking Joe, so I turned IPtables off and did a straight all ports forward on the firewall, and got the same result.

Sigh.

 

[atsak]

But your thinking got me thinking about the idea that the traffic wasn't correctly passing through; which lead me to the externip settings, which were wrong after a backup restore.

Which I fixed and voila.

Thanks.

 

[jroper]

I've not confirmed it for myself, but I understand that T38 requires the following iptables entry.

iptables -A INPUT -p udp -m udp --dport 4000:4999 -j ACCEPT

Joe

 

[atsak]

It's working without that in my configuration, but it *should* require that, you're correct. Incidentally I can't get outbound T.38 to work; the SPA2102 doesn't recognize the call as a fax call according to the log; now I have to figure that one out. Sigh.