No Rx when the C-series codec connected to ISDN Link

[TABISH ANSARI]

We have connected the ISDN Link with the C series codec. The codec IP is NAT to the public IP, the codec is not receiving the far end video and there no Rx on the codec. Even the port open for any/any still the same result. Is this beacause of the ISDN Link ?

[Chad Patterson]

Hey Tabish,

This may have something to do with the NAT configuraiton on the firewall. I would take a packet capture on the codec if you can to see if the codec is advertising its private address for media to be sent to. If this is the case, then it makes sense that you not get inbound media, because the far end is attempting to send RTP to the private address and not the public NAT ip address.

On the endpoint I know there are a few settings where you can select if you are NATing the address of the system. I would check these settings on the endpoint as well.

[TABISH ANSARI]

I tried to use those setting on the endpoint side also, which comes under H323 (NAT address / Mode) but that doesn't help. The internal dialing works good on the internal IP's. only on the scenario when the codec calling out to public network the issue comes in.