SoftIP, FACSys, & Asterisk (faxing not working)

Issue: I am attempting to send Fax’s via the FACsys software using the SoftIP software. I am able to make the call, it appears to connect, but the fax fails with a status of “Remote unit incompatible” in the FACSys Desktop software. Below I have included the output of “sip show channelstats” because it appears that packets are being lost.

SIP GLOBAL includes:
T.38 support: Yes
T.38 EC mode: Redundancy
T.38 MaxDtgrm: -1

I have a Linsys ATA with a fax machine behind a NAT that connects to the same Asterisk box and it is able to send faxes to the destination which the FACSys server cannot.

Setup:

Fax Server
*internal IP behind NAT
*SoftIP Software (dialogic.com/products/ip_ena … re_SIP.htm).
*FACsys faxing software
*connects via SIP proxy to asterisk server

Asterisk Server
*1.8.4-rc2
*behind NAT

sip show channelstats
Peer             Call ID      Duration Recv: Pack  Lost       (     %) Jitter Send: Pack  Lost       (     %) Jitter
<providerIP>   787a8afe620  00:00:18 0000000166  0000000007 ( 4.05%) 0.0000 0000000169  0016776815 (9927109.47%) 0.0002
<externalIP of FACSys Server>    da929008-15  00:00:18 0000000169  0000000000 ( 0.00%) 0.0000 0000000164  0000000000 ( 0.00%) 0.0145
2 active SIP channels

SIP flow from packet capture:

Conv.| Time    | <SoftIP ExternIP>                         | <SIP Provider IP>                        |
     |         |                   | <asterisk internIP>      |                   
0    |30.821   |         INVITE SDP (g711U telephone-eventRTPType-101)          |                   |SIP From: "SoftIP" <sip:softip@server To:sip:<dialed#>@asteriskbox.com
     |         |(5060)   ------------------>  (5060)   |                   |
0    |30.821   |         100 Trying|                   |                   |SIP Status
     |         |(5060)   <------------------  (5060)   |                   |
-----------------------------------------------------------------------------
1    |30.830   |                   |         INVITE SDP (g711U g711A telephone-eventRTPType...1)          |SIP From: "SoftIP" <sip:softip@<server internIP> To:<sip:<dialed#>@provider.com
     |         |                   |(5060)   ------------------>  (5060)   |
1    |30.909   |                   |         100 Trying|                   |SIP Status
     |         |                   |(5060)   <------------------  (5060)   |
1    |38.305   |                   |         183 Session Progress SDP (g711U telephone-even...PType-101)          |SIP Status
     |         |                   |(5060)   <------------------  (5060)   |
-----------------------------------------------------------------------------
0    |38.306   |         183 Session Progress SDP (g711U telephone-even...PType-101)          |                   |SIP Status
     |         |(5060)   <------------------  (5060)   |                   |
-----------------------------------------------------------------------------
1    |41.724   |                   |         200 OK SDP (g711U telephone-eventRTPType-101)          |SIP Status
     |         |                   |(5060)   <------------------  (5060)   |
1    |41.724   |                   |         ACK       |                   |SIP Request
     |         |                   |(5060)   ------------------>  (5060)   |
-----------------------------------------------------------------------------
0    |41.725   |         200 OK SDP (g711U telephone-eventRTPType-101)          |                   |SIP Status
     |         |(5060)   <------------------  (5060)   |                   |
0    |41.747   |         ACK       |                   |                   |SIP Request
     |         |(5060)   ------------------>  (5060)   |                   |
-----------------------------------------------------------------------------
1    |83.103   |                   |         BYE       |                   |SIP Request
     |         |                   |(5060)   <------------------  (5060)   |
1    |83.103   |                   |         200 OK    |                   |SIP Status
     |         |                   |(5060)   ------------------>  (5060)   |
-----------------------------------------------------------------------------
0    |83.104   |         BYE       |                   |                   |SIP Request
     |         |(5060)   <------------------  (5060)   |                   |
0    |83.121   |         200 OK    |                   |                   |SIP Status
     |         |(5060)   ------------------>  (5060)   |                   |
rtp set debug on
Got  RTP packet from    <PROVIDER-IP>:21260 (type 00, seq 029030, ts 2896991065, len 000160)
Got  RTP packet from    <PROVIDER-IP>:21260 (type 00, seq 029031, ts 2896991225, len 000160)
    -- SIP/<PROVIDER-SIP-DNS>.com-00000031 is making progress passing it to SIP/<SOFTIP-HOST>-00000030
Got  RTP packet from    <PROVIDER-IP>:21260 (type 00, seq 029032, ts 2896991385, len 000160)
Sent RTP packet to      <SOFTIP-EXTERNIP>:10052 (type 00, seq 027479, ts 2896991384, len 000160)
Got  RTP packet from    <PROVIDER-IP>:21260 (type 00, seq 029033, ts 2896991545, len 000160)
Sent RTP packet to      <SOFTIP-EXTERNIP>:10052 (type 00, seq 027480, ts 2896991544, len 000160)
Got  RTP packet from    <PROVIDER-IP>:21260 (type 00, seq 029034, ts 2896991705, len 000160)
Sent RTP packet to      <SOFTIP-EXTERNIP>:10052 (type 00, seq 027481, ts 2896991704, len 000160)
Got  RTP packet from    <PROVIDER-IP>:21260 (type 00, seq 029035, ts 2896991865, len 000160)
Sent RTP packet to      <SOFTIP-EXTERNIP>:10052 (type 00, seq 027482, ts 2896991864, len 000160)
Got  RTP packet from    <PROVIDER-IP>:21260 (type 00, seq 029036, ts 2896992025, len 000160)
Sent RTP packet to      <SOFTIP-EXTERNIP>:10052 (type 00, seq 027483, ts 2896992024, len 000160)
Got  RTP packet from    <PROVIDER-IP>:21260 (type 00, seq 029037, ts 2896992185, len 000160)
Sent RTP packet to      <SOFTIP-EXTERNIP>:10052 (type 00, seq 027484, ts 2896992184, len 000160)
Got  RTP packet from    <PROVIDER-IP>:21260 (type 00, seq 029038, ts 2896992345, len 000160)
Sent RTP packet to      <SOFTIP-EXTERNIP>:10052 (type 00, seq 027485, ts 2896992344, len 000160)
Got  RTP packet from    <PROVIDER-IP>:21260 (type 00, seq 029039, ts 2896992505, len 000160)
Sent RTP packet to      <SOFTIP-EXTERNIP>:10052 (type 00, seq 027486, ts 2896992504, len 000160)
Got  RTP packet from    <PROVIDER-IP>:21260 (type 00, seq 029040, ts 2896992665, len 000160)
Sent RTP packet to      <SOFTIP-EXTERNIP>:10052 (type 00, seq 027487, ts 2896992664, len 000160)
Got  RTP packet from    <PROVIDER-IP>:21260 (type 00, seq 029041, ts 2896992825, len 000160)
Sent RTP packet to      <SOFTIP-EXTERNIP>:10052 (type 00, seq 027488, ts 2896992824, len 000160)
Got  RTP packet from    <PROVIDER-IP>:21260 (type 00, seq 029042, ts 2896992985, len 000160)
Sent RTP packet to      <SOFTIP-EXTERNIP>:10052 (type 00, seq 027489, ts 2896992984, len 000160)
Got  RTP packet from    <PROVIDER-IP>:21260 (type 00, seq 029043, ts 2896993145, len 000160)
Sent RTP packet to      <SOFTIP-EXTERNIP>:10052 (type 00, seq 027490, ts 2896993144, len 000160)
    -- SIP/<PROVIDER-SIP-DNS>.com-00000031 answered SIP/<SOFTIPHOST>-00000030

after the call is answered it appears that RTP stops. Maybe due to the face that canreinvite = yes.

changed sip.conf canreinvite = no

[2011-03-16 00:26:27] DEBUG[13222]: res_rtp_asterisk.c:1437 process_dtmf_rfc2833: Ignoring RTP 2833 Event: 00000024. Not a DTMF Digit.
[2011-03-16 00:26:27] DEBUG[13222]: res_rtp_asterisk.c:1437 process_dtmf_rfc2833: Ignoring RTP 2833 Event: 00000024. Not a DTMF Digit.
[2011-03-16 00:26:27] DEBUG[13222]: res_rtp_asterisk.c:1437 process_dtmf_rfc2833: Ignoring RTP 2833 Event: 00000024. Not a DTMF Digit.
asteriskbox*CLI> sip show channelstats
Peer             Call ID      Duration Recv: Pack  Lost       (     %) Jitter Send: Pack  Lost       (     %) Jitter
<PROVIDER-IP>   42d8edb81f5  00:00:51 0000002240  0000000003 ( 0.13%) 0.0000 0000002235  0000000000 ( 0.00%) 0.0013
<SOFTIP-EXTERNIP>    efd6f438-10  00:00:51 0000002701  0000003435 (55.98%) 0.0000 0000002239  0000000000 ( 0.00%) 0.0154
2 active SIP channels

Does anyone have any idea what may be causing this?

Thanks in advance,

Rick