SIP 871 firewall

[jseneca64]

Hello,

I have a 871w 12.4 (11)T1. I am trying to setup a linksys spa942 phone with Trixbox v1.2. Calls last for 30 seconds then I get one way audio out. When I disable the firewall it works just fine.

I've been through 4 cisco engineers and it's still not working. Any sugestions would be greatly appreciated.

thanks,

John

[jseneca64]

Finally resolved by the firewall team. We upgraded to the latest ios, 12.4(15)T5. There was a bug in 12.4(11)T1, See this: CSCsi84069, CBAC blocks RTP traffic even if pre-generated session exists

Under some very specific circumstances with IP inspect, NAT and ip phones located in different VRF's, it might be that SIP inspection is not allowing through the RTP session of called SIP phone.

No known workaround

Thank you,

John