asterisk users - Jun 2013 - Asterisk T.38 Pass-Through doesn't work

What I have is:
* Asterisk 1.8.10.1~dfsg-1ubuntu1,
* SPA112 ATA with analog fax in 1-st FXS port connected,
* SIP trunk with provider supporting T.38.

My network looks like this:
* spa112 (192.168.33.200/24) and Asterisk (192.168.5.253/24) in 
neighbouring LANs,
* Asterisk connects to the provider (80.75.130.136) via router 
(82.200.7.184). Router has full DNAT to Asterisk server.

What happens?
* The fax from SPA112 to Asterisk cmd ReceiveFax works well,
* The fax from Asterisk cmd SendFax to PSTN fax works well,
* However, the fax from SPA112 to PSTN fax doesn't work. Using udptl 
debug, I can see packets between Asterisk and both sides (SPA112 and 
PSTN fax) but it seems that faxes can't agree how to send image.

== sip.conf:
[general]
tcpenable=yes
videosupport=yes
transport=udp,tcp
dtmfmode=rfc2833
qualify=yes
directmedia=no
allowguest=no
alwaysauthreject=yes
rtcachefriends=yes
rtupdate=no
callcounter=yes
t38pt_udptl=yes,redundancy,maxdatagram=200
t38pt_rtp=no
t38pt_tcp=no
ignoresdpversion=yes
disallow=all
allow=alaw
allow=ulaw
externip=82.200.7.184
localnet=192.168.0.0/255.255.0.0

[mtt]
type=peer
host=80.75.130.136
fromuser=74957777777
disallow=all
allow=alaw,ulaw
directmedia=no
canreinvite=no
nat=yes

== udptl.conf:
[general]
udptlstart=4000
udptlend=4999
T38FaxUdpEC=t38UDPRedundancy
T38FaxMaxDatagram=200
udptlfecentries = 3
udptlfecspan = 3
use_even_ports = no

== spa112 SIP settings screenshot:
http://tinypic.com/view.php?pic=2z8dic6&s=5

== debug log:
https://gist.github.com/anonymous/5685307

Please, help me!

On 2/06/2013 9:34 PM, ?????? ??????? wrote:
> What I have is:
> * Asterisk 1.8.10.1~dfsg-1ubuntu1,
> * SPA112 ATA with analog fax in 1-st FXS port connected,
> * SIP trunk with provider supporting T.38.
>
> My network looks like this:
> * spa112 (192.168.33.200/24) and Asterisk (192.168.5.253/24) in
> neighbouring LANs,
> * Asterisk connects to the provider (80.75.130.136) via router
> (82.200.7.184). Router has full DNAT to Asterisk server.
>
> What happens?
> * The fax from SPA112 to Asterisk cmd ReceiveFax works well,
> * The fax from Asterisk cmd SendFax to PSTN fax works well,
> * However, the fax from SPA112 to PSTN fax doesn't work. Using udptl
> debug, I can see packets between Asterisk and both sides (SPA112 and
> PSTN fax) but it seems that faxes can't agree how to send image.
>
> == sip.conf:
> [general]
> tcpenable=yes
> videosupport=yes
> transport=udp,tcp
> dtmfmode=rfc2833
> qualify=yes
> directmedia=no
> allowguest=no
> alwaysauthreject=yes
> rtcachefriends=yes
> rtupdate=no
> callcounter=yes
> t38pt_udptl=yes,redundancy,maxdatagram=200
> t38pt_rtp=no
> t38pt_tcp=no
> ignoresdpversion=yes
> disallow=all
> allow=alaw
> allow=ulaw
> externip=82.200.7.184
> localnet=192.168.0.0/255.255.0.0
>
> [mtt]
> type=peer
> host=80.75.130.136
> fromuser=74957777777
> disallow=all
> allow=alaw,ulaw
> directmedia=no
> canreinvite=no
> nat=yes
>
> == udptl.conf:
> [general]
> udptlstart=4000
> udptlend=4999
> T38FaxUdpEC=t38UDPRedundancy
> T38FaxMaxDatagram=200
> udptlfecentries = 3
> udptlfecspan = 3
> use_even_ports = no
>

I don't have access to one of these devices though some suggestions you 
could try;

1) On SPA112 set "FAX T38 Redundancy" = 3
2) Add t38pt_usertpsource=yes in [mtt] section
3) Change maxdatagram=200 to maxdatagram=1400
4) In udptl.conf change T38FaxMaxDatagram to a value of 1400
5) In udptl.conf change use_even_ports to yes


You don't appear to list the sip.conf entry for the SPA112.

Where did t38pt_rtp & t38_tcp come from?

You may also want to experiment with the SPA112 setting "FAX T38 ECM
Enable"

Cheers,

Larry.