T38 VoIP Provider inbound Fax Problem

[lploscar]

Hello Everyone,

I have the licensed version of 3CX, and till yesterday everything was working like a charm ... then, the requirement to receive faxes to email came into the picture. I have the default Fax Server ext. 888 configured with a DID, and was testing to see if I can receive faxes to email from outside. No go... Got the etch support (from the SIP trunk provider) on the phone, and after running a trace/capture they emailed me the following:

"Here's a call trace where you can see that your system swaps from TCP to UDP in the same call which is not allowed by Colt system.

Please take care about the following 2 RecNO’s:

1 19/01/2012 13:36:25 984 VoIP SIP 46090 1011 - 100.100.100.100 222.222.222.222 - - Method=INVITE, Method=INVITE


00000110 Transport 6 TCP

And then:

5 19/01/2012 13:36:27 872 VoIP SIP 46090 900 - 222.222.222.222 100.100.100.100 - - Method=INVITE, Method=INVITE

00010001 Transport 17 UDP


After this message from your system we can see that Colt system is disconnection the connection with 488 Not Acceptable Here as it can’t go further
with protocol change in the middle of session.

6 19/01/2012 13:36:27 875 VoIP SIP 46090 326 - 100.100.100.100 222.222.222.222 - - Status=SIP/2.0 488 Not Acceptable Here, Method=INVITE

IP & Transport Layers Summary
00010001 Transport 17 UDP
00000100 IP Address Type 4 IPv4
-------- Source Address 222.222.222.222
-------- Destination Address 100.100.100.100
-------- Source Port 5060 SIP
-------- Destination Port 5060 SIP
Session Initiation Protocol
-------- Status SIP/2.0 488 Not Acceptable Here

Please try to change your setting so that your system will stay within TCP from beginning to end of the session."


Any help would be greatly appreciated...
(full capture/trace attached)

Thank you,

Luc P.

*edited to add the attachment

 

[lploscar]

Problem solved, please close. Provider changed their Invite parameters to allow only TCP... everything works now.