Connecting to VoIP provider behind ISA2004

Khattab

Hi,

I need to get your thoughts on a problem i've been experiencing.

We are running a win2003 network, ISA2004 yada yada yada. I have a VoIP device through an external provider which at one point in time, was running perfectly. Lately however, i might as well not even have the darn thing.

When i first turn the device on, it connects right up and works for about 10 minutes (if it's idle). I dont know what the problem is exactly, but all i know is that the only way i can ever use it, is to turn it off and turn it back on, in which case it automatically establishes a connection with the provider, i make my phone call and then 10 minutes after i hang up, it disconnects like clock work.

We are using IAX, not SIP. I have been doing some reading and it seems as though it is an issue with NAT? I believe the issue must be related to NAT because if i give my VoIP device an external IP address, it connects and remains connected the entire time. Behind the ISA Firewall though, it cant stay connected for more than 10minutes.

Any idea on how i can fix this problem so that my device will actually remain connected?
I'm far from being an expert, so please be as precise as possible.

Thanks!
K

Edit: I spoke to my VoIP providers who said that the delay between the two points is 900ms.

Khattab

no responses from anyone??

Does no one have any ideas as to how this can be fixed?

In that case, let me check to make sure that i've done everything correctly......

In ISA 2004, i have created a firewall rule to allow the VoIP device out externally. I believe that rule is working fine. The logging tool is ISA doesnt show any blocked requests, everything looks great.

The other thing i've done, is i've created a server publishing rule for my VoIP device using port 4569. I created the port definition and under the "Firewall Ports" section, set it to be published on port 4575. Under the "Published Server Ports" section, ive set it to 4569. It is listening for the requests on the external interface.

Below is a copy of the result when i do a netstat -an

C:\Documents and Settings\admin>netstat -an | find "4575"
UDP x.x.x.x:4575 *:* (where x.x.x.x is my external interface).

Have i done anything wrong or have i missed anything?

I need the phone to be fully functional ASAP.

networker050184

I only have experience with SIP, but it sounds like the NAT entry for your registration is timing out. Not a MS guy myself so I can't really give you much insight on how to fix it though.

HeroPsycho

Khattab wrote: »

no responses from anyone??

Does no one have any ideas as to how this can be fixed?

In that case, let me check to make sure that i've done everything correctly......

In ISA 2004, i have created a firewall rule to allow the VoIP device out externally. I believe that rule is working fine. The logging tool is ISA doesnt show any blocked requests, everything looks great.

The other thing i've done, is i've created a server publishing rule for my VoIP device using port 4569. I created the port definition and under the "Firewall Ports" section, set it to be published on port 4575. Under the "Published Server Ports" section, ive set it to 4569. It is listening for the requests on the external interface.

Below is a copy of the result when i do a netstat -an

C:\Documents and Settings\admin>netstat -an | find "4575"
UDP x.x.x.x:4575 *:* (where x.x.x.x is my external interface).

Have i done anything wrong or have i missed anything?

I need the phone to be fully functional ASAP.

If you haven't installed ISA 2004 SP3 yet, I highly recommend doing so to increase the logging capabilities to help you resolve this issue.

You need to use the monitoring tab and setup filters and begin logging to see if ISA is dropping the connections or something.

There's no sense guessing if ISA is the reason. Find out for sure.