INVITE sip:729719@1.2.3.4;user=phone SIP/2.0 
Via: SIP/2.0/UDP 5.6.7.8:5060;branch=z9hG4bK33a7f564;rport 
From: <sip:855245@5.6.7.8:5060;user=phone>;tag=as26993d20 
To: <sip:729719@1.2.3.4;user=phone>;tag=ff785c00ffff0210ff0000104b07ff58 
Contact: <sip:855245@5.6.7.8> 
Call-ID: 06755c00b0ab0210800000104b07c258@ss 
CSeq: 102 INVITE 
User-Agent: Asterisk PBX 
Max-Forwards: 70 
Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, SUBSCRIBE, NOTIFY 
Supported: replaces 
X-asterisk-info: SIP re-invite (T38 switchover) 
Content-Type: application/sdp 
Content-Length: 351 

v=0 
o=root 5767 5768 IN IP4 5.6.7.8 
s=session 
c=IN IP4 5.6.7.8 
t=0 0 
m=image 4145 udptl t38 
a=T38FaxVersion:0 
a=T38MaxBitRate:9600 
a=T38FaxFillBitRemoval:0 
a=T38FaxTranscodingMMR:0 
a=T38FaxTranscodingJBIG:0 
a=T38FaxRateManagement:transferredTCF 
a=T38FaxMaxBuffer:200 
a=T38FaxMaxDatagram:200 
a=T38FaxUdpEC:t38UDPRedundancy 

--- 
<--- SIP read from 1.2.3.4:5060 ---> 
SIP/2.0 200 OK 
Via: SIP/2.0/UDP 5.6.7.8:5060;branch=z9hG4bK33a7f564;rport 
From: <sip:855245@5.6.7.8:5060;user=phone>;tag=as26993d20 
To: <sip:729719@1.2.3.4;user=phone>;tag=ff785c00ffff0210ff0000104b07ff58 
Call-ID: 06755c00b0ab0210800000104b07c258@ss 
CSeq: 102 INVITE 
Server: MERA MSIP v.1.0.1 
Content-Type: application/sdp 
Content-Length: 187 

v=0 
o=- 1174580156 1174580156 IN IP4 1.2.3.4 
s=- 
c=IN IP4 1.2.3.4 
t=0 0 
m=image 22640 udptl t38 
a=T38FaxRateManagement:transferredTCF 
a=T38FaxUdpEC:t38UDPRedundancy 

<-------------> 

INVITE sip:125@10.7.8.125:5060 SIP/2.0 
Via: SIP/2.0/UDP 10.7.8.254:5060;branch=z9hG4bK5ad9eb11;rport 
From: "102" <sip:102@10.7.8.254>;tag=as37d18976 
To: <sip:125@10.7.8.125:5060>;tag=6b0cc7c7820a909ai0 
Contact: <sip:102@10.7.8.254> 
Call-ID: 3b9f31c677109b700a2443ca3daf644f@10.7.8.254 
CSeq: 103 INVITE 
User-Agent: Asterisk PBX 
Max-Forwards: 70 
Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, SUBSCRIBE, NOTIFY 
Supported: replaces 
X-asterisk-info: SIP re-invite (T38 switchover) 
Content-Type: application/sdp 
Content-Length: 343 

v=0 
o=root 5767 5768 IN IP4 10.7.8.254 
s=session 
c=IN IP4 10.7.8.254 
t=0 0 
m=image 4642 udptl t38 
a=T38FaxVersion:0 
a=T38MaxBitRate:9600 
a=T38FaxFillBitRemoval:0 
a=T38FaxTranscodingMMR:0 
a=T38FaxTranscodingJBIG:0 
a=T38FaxRateManagement:transferredTCF 
a=T38FaxMaxBuffer:200 
a=T38FaxMaxDatagram:200 
a=T38FaxUdpEC:t38UDPRedundancy 

--- 
<--- SIP read from 10.7.8.125:5060 ---> 
SIP/2.0 200 OK 
To: <sip:125@10.7.8.125:5060>;tag=6b0cc7c7820a909ai0 
From: "102" <sip:102@10.7.8.254>;tag=as37d18976 
Call-ID: 3b9f31c677109b700a2443ca3daf644f@10.7.8.254 
CSeq: 103 INVITE 
Via: SIP/2.0/UDP 10.7.8.254:5060;branch=z9hG4bK5ad9eb11 
Contact: <sip:125@10.7.8.125:5060> 
Server: Linksys/SPA2100-3.3.6 
Content-Length: 265 
Content-Type: application/sdp 

v=0 
o=- 10509957 10509957 IN IP4 10.7.8.125 
s=- 
c=IN IP4 10.7.8.125 
t=0 0 
m=image 16432 udptl t38 
a=T38FaxVersion:0 
a=T38MaxBitRate:14400 
a=T38FaxRateManagement:transferredTCF 
a=T38FaxMaxBuffer:200 
a=T38FaxMaxDatagram:200 
a=T38FaxUdpEC:t38UDPRedundancy 
<------------->  

v=0
o=rtp 1160124458839569000 160124458839569000 IN IP4 10.69.255.242
s=-
c=IN IP4 10.69.255.242
t=0 0
m=image 5004 UDPTL t38
a=T38FaxVersion:0
a=T38MaxBitRate:14400
a=T38FaxMaxBuffer:1024
a=T38FaxMaxDatagram:238
a=T38FaxRateManagement:transferredTCF
a=T38FaxUdpEC:t38UDPRedundancy

with the one proxied by Asterisk:

v=0
o=root 5371 5372 IN IP4 10.69.255.242
s=session
c=IN IP4 10.69.255.242
t=0 0
m=image 5004 udptl t38
a=T38FaxVersion:0
a=T38MaxBitRate:9600
a=T38FaxFillBitRemoval:0
a=T38FaxTranscodingMMR:0
a=T38FaxTranscodingJBIG:0
a=T38FaxRateManagement:transferredTCF
a=T38FaxMaxBuffer:238
a=T38FaxMaxDatagram:238
a=T38FaxUdpEC:t38UDPRedundancy


INVITE sip:+1-212-555-1234@bell-tel.com SIP/2.0
Via: SIP/2.0/UDP kton.bell-tel.com
From: A. Bell <sip:+1-519-555-1234@bell-tel.com>
To: T. Watson <sip:+1-212-555-1234@bell-tel.com>
Call-ID: 3298420296@kton.bell-tel.com
Cseq: 1 INVITE
Subject: Mr. Watson, here is a fax
Content-Type: application/sdp
Content-Length: 
v=0
o=faxgw1 2890844526 2890842807 IN IP4 128.59.19.68
e=+1-212-555-1234@bell-tel.com
t=2873397496 0
c=IN IP4 128.59.19.68
m=audio 49170 RTP/AVP 100 101
a=rtpmap:100 t38/8000
a=fmtp:100 T38FaxRateManagement=transferredTCF
a=rtpmap:101 parityfec/8000
a=fmtp:101 49173 IN IP4 128.59.19.68
m=image 49172 tcp t38
a=T38FaxRateManagement :localTCF



INVITE sip:fax@192.168.1.10:5070 SIP/2.0 
Via: SIP/2.0/UDP 192.168.1.1:5060;branch=z9hG4bK-dmq-22232;rport 
From: <sip:vigor@192.168.1.1:5060>;tag=lpX-1519 
To: "Fax" <sip:fax@192.168.1.10:5070>;tag=1146418687 
Call-ID: A359409E-39D1-9052-7EC7-33621206A204@192.168.1.10 
CSeq: 2 INVITE 
Contact: <sip:vigor@192.168.1.1> 
Max-Forwards: 70 
User-Agent: DrayTek UA-1.2.1 
Content-Type: application/sdp 
Content-Length: 263 

v=0 
o=vigor 5972727 56415 IN IP4 192.168.1.1 
s=SIP Call 
c=IN IP4 192.168.1.1 
t=0 0 
m=image 40002 udptl t38 
a=T38FaxVersion:0 
a=T38MaxBitRate:14400 
a=T38FaxRateManagement:transferredTCF 
a=T38FaxUdpEC:t38UDPFEC 
a=T38FaxUdpEC:t38UDPRedundancy 
a=sendrecv