A router doesn't understand that it's RFC1918. It understands gateways, who gets the packet if it doesn't know what to do with it. Yes, personification of a router. Some companies install ACL's which prevent this type of traffic but remember a router could be used internally so it must be able to pass RFC1918 traffic (if your using this particular block internally). Some cable companies have internal networks that are RFC1918, so that they may remotely administrate the routers using "private" networks thusly the cause of your double hop to destination unreachable.
Matthew F. Caldwell, CISSP Chief Security Officer GuardedNet, Inc. [EMAIL PROTECTED] www.guarded.net -----Original Message----- From: Ian Webb [mailto:[EMAIL PROTECTED]] Sent: Sunday, July 21, 2002 5:27 PM To: [EMAIL PROTECTED] Subject: Strange traceroute output on Road Runner for an RFC 1918 address I get the following output when I do a traceroute from my Windows XP machine, which is directly connected to a Road Runner cable modem (Motorola Surfboard), to 192.168.100.1: C:\>tracert 192.168.100.1 Tracing route to 192.168.100.1 over a maximum of 30 hops 1 * * * Request timed out. 2 62 ms 125 ms 66 ms 24.93.66.37 3 87 ms 220 ms * 24.93.66.150 4 * 24.93.66.177 reports: Destination host unreachable. This seems weird to me, since 192.168.100.1 is an RFC 1918 local address space. I can't think of any valid reason that a packet destined for it would go *two* hops into Road Runner's network before getting a destination host unreachable. Is there something I'm missing? Thanks, Ian
