[asterisk-users] UDPTL T38 via NAT

[Remco Bressers]

Dear list,

I've got the following setup :

[FAX-ATA]--[PBX LAN]--[Firewall]--[PBX WAN]-----[upstream SIP]

On the PBX's we run Asterisk 1.4.33 with t38pt_udptl=yes in [general].
The FAX ATA is a Teles VoIPBox with T.38 support (that works). On the
PBX WAN, i see the following in udptl debug :

Sent UDPTL packet to 172.16.0.156:4460 (type 0, seq 184, len 32)
Got UDPTL packet from 62.180.xx.xx:36170 (type 0, seq 0, len 32)
Sent UDPTL packet to 172.16.0.156:4460 (type 0, seq 185, len 32)
Got UDPTL packet from 62.180.xx.xx:36170 (type 0, seq 0, len 32)
Sent UDPTL packet to 172.16.0.156:4460 (type 0, seq 186, len 32)
Got UDPTL packet from 62.180.xx.xx:36170 (type 0, seq 0, len 29)

This means my outgoing udptl traffic is correctly translated, but
somehow i'm sending 172.16.0.156 instead of my public IP address on the
firewall.

On the LAN PBX, i've got the following config :

[general]
t38pt_udptl=yes

[202]
type=friend
secret=***
username=202
regexten=202
host=dynamic
canreinvite=yes
allow=alaw
context=local
qualify=yes

On the WAN PBX, the config for the trunk is the following :

[general]
t38pt_udptl=yes

[trunk]
type=peer
context=trunk-in
host=62.180.xxx.xxx
port=5070
disallow=all
allow=alaw
allow=ulaw
qualify=yes
nat=no


Can anybody tell me how to change this behaviour? Fax isn't working
ofcourse.

-- 
Kind regards,
Signet bv


Remco Bressers

T 040 - 707 4 907
F 040 - 707 4 909
E rbressers at signet.nl