<measl@mfn.org> said:
As for "How", remember that private space is no different from public space, except for the "gentlemans agreement" we all have not to route it externally. For use as transit networks, private space _almost always_ a Good Idea.
Umm, it's socially irresponsible. Traceroutes through RFC-1918 space are worthless. My reverse lookups don't work for your private addresses meaning that I have no idea who's network is eating the packets. Even worse is when they overlap with a local set. Traceroutes through local 10.0.0.0 into ISP 10.0.0.0 are extraordinarily confusing when ISP-B's routers are showing up as RTR-x.local.net. What fun figuring out why there's a router loop through my first hop after it's already left that network. Also a blast trying to decipher ICMP errors like host unreachable and Frag Req'd messages that appear to orignate from nowhere in particular. You should also be ingress/egress filtering packets with these addresses. That means no traceroutes, no path MTU discovery, no errors, no nothing. If you or your peers aren't having problems, then you aren't filtering. It's anti-clever to use RFC 1918 space on public networks. I'm sorry that it's too much work to use valid addresses on your network but please don't try to pass it off as being good behavior. -- Eric A. Hall http://www.ehsco.com/ Internet Core Protocols http://www.oreilly.com/catalog/coreprot/