static routes

carl_townshend · ‎03-24-2006

is there any reason why we would create a static route point to null 0, surely if there was no route present it would drop the packer anyway, or is this used when we use routing protocols ?

tekha · ‎03-24-2006

Well I have it on the router accessing the Internet, because I have a default route, everything gets routed to that router. even RFC1918 address, but I don't want to route these addresses to the Internet, so I placed the following three routes on the router.

ip route 10.0.0.0 255.0.0.0 Null0

ip route 172.16.0.0 255.240.0.0 Null0

ip route 192.168.0.0 255.255.0.0 Null0

You could allso use this as a simple form of access filtering.

carl_townshend · ‎03-25-2006

SO BASICALLY IT WOULDNT LET THESE ADDRESSES THROUGH TO THE INTERNET ?

tekha · ‎03-25-2006

Yes insteed of following the default route, it would be dropped.

If you have ever seen a network completly infected with virus, you have probably noticed that infected host send packets to all sorts of rfc1918 address, these would get dropped by a route to a Null0 interface.