12 Apr
2010
12 Apr
'10
9:37 a.m.
Well, we know that some sites run Net 1 behind a NAT when they should be running an RFC 1918 prefix. We also know that pretty much everbody is configured to drop RFC 1918 destination packets, but since Net 1 is a valid prefix there is no reason to drop it.
So the real question is probably: why are packets being sent to addresses that are behind NATs?
Put it this way, if a device that implement NAT, translates the 1/8 IP address to the real IPs the customer owns and has a subnet within 1/8 directly attached, but also participates in dynamic routing with border routers or ISP routers, whether you use NAT or not, the 1/8 network will be injected into the ISP's routing tables ...