2800 ISR SIP

Unanswered Question
Jun 10th, 2008


Here is the situation: I have a 2850ISR with 12.4XW5 software. The router is doing PAT to the Internet and a wireless bridge. I connect via wireless with on a Macbook with iChat. I fire up the SIP based audio and video collaboration. I cannot connect audio video with another client. I use the command no ip nat service sip udp port 5060. Now, I can connect every time with iChat Audio Video. Now, I move to a 2825 ISR with 12.4XW5 software. The router has a routable wireless interface (no bridge interface) and does not have NAT/PAT enabled on any interface. I connect to the wireless network. The iChat Audio video only will connect if one side initiates. I do not understand, the router should simply be routing the traffic because NAT is not enabled. There are no Access Lists and there is no IPS/IDS or firewall enabled. I've compared configs between the 2825 and the 2850 routers and do not see anything blatant. Questions: Does a router that does not have NAT enabled still need the no ip nat service sip udp port 5060 in order to disable the application layer gateway feature? Would the difference between wireless interfaces, one being a BVI interface and the other being the actual physical dot11 interface have anything to do my problems? Thanks and any suggestions or help will be much appreciated!

I have this problem too.
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richard.gosling Wed, 06/11/2008 - 01:40


Have you created a BVI interface and Bridged with dot1 to it?

You will need nat inside and outside, also set the BVI as inside NAT

You will need to nat port 5060 source port and 5060 as the destination port on the NAT/PAT

sweigle Mon, 06/16/2008 - 09:03


Thanks for your reply! To recap to make sure I understand, Even though I do not need NAT in this scenario, I do have to enable NAT to allow SIP to flow through the router? Also, do I need to create a BVI interface to allow sip? Why can't I just use the physical Dot11 interface?



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