One way audio behind NAT on 2851, is ALG running properly?

Unanswered Question
Apr 9th, 2008


I have an IP phone behind a NAT gateway which is registering with a CM 6.1 system (which is on a public IP).

I have added ip inspect rules for the following:

ip inspect name voip rtsp timeout 5

ip inspect name voip skinny

ip inspect name voip h323

ip inspect name voip h323callsigalt

ip inspect name voip sqlnet

ip inspect name voip streamworks

ip inspect name voip tftp

ip inspect name voip tcp

ip inspect name voip udp

ip inspect name voip vdolive

ip inspect name voip icmp

I have added ip inspect rules for both in and out.

Do I need to add an ACL somewhere to force the traffic via the ALG rules as I am permitting all traffic currently to the NAT'd IP range.

I see the following during a call:

Established Sessions

Session 494A176C (>(callmanager2:2000) skinny SIS_OPEN

Session 494A1A3C (>(callmanager1:2000) skinny SIS_OPEN

Session 494A03BC (>(voip-gateway-3845:19484) skinny-RTP-data


Pre-generated Sessions

Pre-gen session 494A149C voip-gateway-3845[1024:65535]=>[23068:23068] skinny-RTP-data

However I cannot get audio in to the phone however out works fine.

I have tried a 'no nat service rtsp' however I get the following error: "NAT: Can't get system defined port"

Is there something I am missing?


I have this problem too.
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ivillegas Tue, 04/15/2008 - 05:09

Looks like you are using NBAR and NBAR will not let you remove the default port.


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