Re: [44net] AMPRNet Interoperability with BGP

Since this is a recurring question, what NAT has to do with this... Scenario: unknown 44net destination address, possible BGP announced: - To operate a tunnel, one needs a public IP as an endpoint (if not BGP routed). - All outgoing 44net traffic will usually originate from the local 44.x.x.x address and go via IPIP tunnels to their partners - Replies will return via the same tunnel - If the destination 44net IP has no known route, it will go the default route, still being originated from a 44.x.x.x address. - If the ISP has source filtering it will end here - If the ISP accepts source 44.x.x.x it will reach the endpoind (let's say a BGP routed IP) via regular internet - The reply will be routed back to ampr-gw (since that is the route for all 44/8 traffic if not specified by a tighter BGP route). - Since ampr-gw does not route data from 44net addresses from the internet to 44net addresses on tunnels, it will die here. So, in these conditions, communications are not possible. And here comes NAT into play: - unknown 44net destinations will be src-nated from the originating 44.x.x.x to the GW's public IP - it will be routed from this public IP to the destination 44net system - replies will be routed back to the originating system - replies will be dst-nated utomatically and forwarded back to the originator. And voila, it works flawless. Marius, YO2LOJ