cancel
Showing results for 
Search instead for 
Did you mean: 
cancel
Announcements

Welcome to the Cisco Small Business Community

Have a question? Click on a topic board below to get started in the community.
Get the latest news in this issue of the Cisco Small Business Monthly Newsletter

1445
Views
0
Helpful
3
Replies
Highlighted
Beginner

SPA2102 T.38 Port Range

We've got a SPA2102 installed behind a client's very, very restrictive firewall.    They block all outgoing ports by default.

We've had them add rules to allow SIP traffic on 5060 and the default RTP port range of 16384 to 16482.

This all works just perfectly and calls in and work as expected.

However, faxes fail every time.   In looking at the firewall rules it appears the SPA2102 is sending T.38 packets over very different port numbers and they are being blocked.   In our tests we saw sessions on ports 4242, 4671 and 4899 so it looks like the range if pretty broad.

My questions are:

1) What range of addresses will be used for T.38

2) Is it possible to change that range to a smaller one so we can have them open those ports in the firewall.   Since the SPA2102 can only do one T.38 session at a time I wouldn't think the range need be all that large.

Everyone's tags (4)
3 REPLIES 3
Highlighted
Cisco Employee

Re: SPA2102 T.38 Port Range

Dear Chris;

I've escalated the question, please stay tuned.

Regards
Alberto

Highlighted
Beginner

Re: SPA2102 T.38 Port Range

I believe that this range is determined by the other end.    At least in our case I'm pretty sure that is the case.

Chris

Highlighted
Cisco Employee

Re: SPA2102 T.38 Port Range

Hi Chris;

I can confirm your assumption, this is selected by the other end. Suggest you check for this with your ITSP.

Regards
Alberto