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New Member

SIP and CallManager Express 4.0

I have SIP trunk to a vendor Viatalk. If I put the CME on the edge of the network so one of its interfaces is directly on the internet the SIP trunk activates and works propery, but it does not seem to work behind another router running IOS firewall doing NAT. The Linksys PAP2 that it comes with DOES work behind the firewall for the same account. Does CME SIP trunking work with NAT?

Hall of Fame Super Gold

Re: SIP and CallManager Express 4.0

Which firewall is that ?

Have you checked the nat option under sip-ua ?

New Member

Re: SIP and CallManager Express 4.0

Its a router running IOS firewall. Yes I have tried all the interations of NAT under sip-ua, as well as enableing SIP support on the firewall (inspect SIP).

Hall of Fame Super Gold

Re: SIP and CallManager Express 4.0

A (recent) NAT IOS router is supposed to have fixup for SIP. Check that it is is changing from address as supposed and it opens port for rtp. If it doesn't, the case should be given to TAC.