I seem to recall that 192.0.2.0/24 was reserved for just this type of use.
Useless for fully-connected example purposes since you won't get any packets back.
-- Eric A. Hall http://www.ehsco.com/ Internet Core Protocols http://www.oreilly.com/catalog/coreprot/
192.0.2.0/24 was earmarked by Jon Postel for use in documentation. Not all (in fact few) protocols are routing oriented so you don't have to show "fully-connected" state. Of course, with VLSM in play, its pretty easy to carve up a /24 into lots of subnets. It was never to show up in a routing table as a prefix that would be forwarded. This was back in the day when oen didn't need and RFC to wipe ones nose. The DSUA draft is prolly the closest document that will exist on this particular prefix. --bill