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Unanswered Question
May 30th, 2008
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I have a MGCP gateway connecting to CCM 6.1 over a serial interface through a firewall. I configured MGCP bind media and control source interface to be loopback1. However, the firewall is seeing that the MGCP gateway is using the serial interface address in the MGCP communication with the CCM. Any ideas why the loopback1 address is not being used?


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Michael Owuor Fri, 05/30/2008 - 16:01
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Hi Sandy,

A few questions for you.

Which specific platform is the gateway, and which IOS is it currently on?

Have the MGCP gateway endpoints actually registered to CUCM? If yes, which address did they register with?

How many hops away from the gateway is the firewall?

A reset of the MGCP process might kick start and to correct any issues.



s.kho Fri, 05/30/2008 - 17:55
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It is a 2811 running 12.5(15)T5. The CUCM is showing the registered gateway address as the loopback1 address, but the firewall is seeing serial ip address for the MGCP communications.

The gateway was rebooted after the issue was first identified, but there was no change. The gateway is 2 hops away.


maharris Fri, 05/30/2008 - 20:01
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I think that there is still some traffic between the gateway and the CUCM that is not technically MGCP, like the config download, and I am not sure about the TCP backhaul traffic. The fact that it shows registered with the loopback address makes it look like at least the basic MGCP stuff is coming from the correct address. If you do a debug mgcp packet, you should see the addresses being used, and could verify that. There are also debugs for the ccm-manager config download, and the tcp backhaul, just to see what the router thinks he is sending.

Mary Beth


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