North American Network Operators Group|
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Re: General question on rfc1918
Joe Abley (jabley) writes: > > You drop the packet at your border before it is sent out to the Internet. > > This is why numbering interfaces in the data path of non-internal traffic is > a bad idea. Unfortunately many providers have the bad habit of using RFC1918 for interconnect, on the basis that a) it saves IPs b) it makes the interconnect "not vulnerable" . > > Packets which are strictly error/status reporting -- e.g. IMP > > 'unreachable', > > 'ttl exceeded', 'redirect', etc. -- should *NOT* be filtered at network > > boundaries _solely_ because of an RFC1918 source address. > > I respectfully disagree. Same here, and even if egress filtering didn't catch it, many inbound filters will.  I'v also heard of ISPs having an entire /16 of routable addresses for their interconnect, but they just don't advertise to peers.