CCM, gateway and FW

Oct 26, 2005 1 Replies

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JS 20 years ago

I have a CCM and a H323-gateway at the office. The gateway has a E1 ISDN out to the PSTN. I have now tried to install a Firewall between the CCM/IP-phones and the Gateway.

Outgoing calls to pstn works fine with the FW in between, but incoming calls does not. The call reaches the phone, but gets immidiately disconnected, and I can see 1 missed call on the phone.The caller gets the ringback tone, but the phone does not ring.

The FW only has one rule at the moment, permit any any. I can not see any traffic from/to my phone being dropped on the FW. Routing works fine between CCM/FW/gateway/phones.

Where should I start looking for the problem?

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CiscoHeadsetAdapter.com 20 years ago

Most likely it's NAT problem. Could you put a sniffer to the LAN between GW and FW and see what happens after call is made? Do you have proper settings on your GW? If you installed the firewall between GW and CCM, you must be doing some NAT. If traffic goes from the CCM to GW, it does automatic NAT translation as regular outbound traffic. But inbound traffic probably should have static NAT translation.

Mike

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