nanog mailing list archives

Re: Routing through non-addressable space???


From: Valdis.Kletnieks () vt edu
Date: Fri, 25 Jan 2002 22:31:26 -0500

On Fri, 25 Jan 2002 18:46:55 PST, Simon Higgs <simon () higgs com>  said:

Can someone explain this trace to me. How on earth did the 10.0.0.0 network 
get inserted into the last hop?

#    IP address       Host name                                Round trip time

4    24.130.2.243     GSR1-SRP4-0.lsanhe4.we.mediaone.net 64 ms
5    24.130.2.242     GSR2-SRP4-0.lsanhe3.we.mediaone.net 71 ms
6    12.125.98.13     Unavailable                         79 ms
7    12.123.28.94     gbr2-p100.la2ca.ip.att.net          94 ms
8                     No response
9    12.122.11.226    ggr1-p340.la2ca.ip.att.net          110 ms
10   192.205.32.246   att-gw.la.home.net                  112 ms
11   24.7.74.182      wbb1-pos2-0.pop1.ca.home.net        120 ms
12   10.252.25.118    Unavailable                         134 ms
13   209.125.128.80   Unavailable                         141 ms

Some naughty person used RFC1918 address space to number their point-to-point
links?  That's OK, until they throw an ICMP error that gets tossed by a
border router that does bogon filtering.  Single biggest reason why
Path MTU Discovery doesn't work, except for maybe sites that stomp on all
the ICMP traffic they see....

-- 
                                Valdis Kletnieks
                                Computer Systems Senior Engineer
                                Virginia Tech

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