SIP proxy or NAT on ASA?

chuck007 · ‎10-05-2009

We need to bring in our SIP provider through a publicly addressed connetion and need to NAT it on the firewall. But the NAT only changes the source or destination address of the IP packet. How can we also NAT the SIP body messages for INVITE commands etc? Does the ASA support this? Thanks alot.

Jon Marshall · ‎10-05-2009

Chuck

The ASA does indeed have support for SIP, this document should get you going -

http://www.cisco.com/en/US/products/ps6120/products_configuration_example09186a008081042c.shtml#sip

Jon

chuck007 · ‎10-05-2009

I did read through that, however it's mainly dealing with inspection as a firewall rather than the SIP translation of the IP address within the body of the packet. We have the basic NAT turned on, but it's not working because SIP embeds the IP inside. If you came across an example how to fix this, I would greatly appreciate it. Or maybe this type of packet translation is just not supported on the ASAs. Thanks.

chuck007 · ‎10-05-2009

I did read through that, however it's mainly dealing with inspection as a firewall rather than the SIP translation of the IP address within the body of the packet. We have the basic NAT turned on, but it's not working because SIP embeds the IP inside. If you came across an example how to fix this, I would greatly appreciate it. Or maybe this type of packet translation is just not supported on the ASAs. Thanks.