nanog mailing list archives

Re: Wrong use of 100.64.0.0/10


From: "Justin M. Streiner" <streiner () cluebyfour org>
Date: Fri, 2 Oct 2015 10:52:15 -0400 (EDT)

On Fri, 2 Oct 2015, Marco Paesani wrote:

Hi,
probably this route is wrong, see RFC 6598, as you can see:

show route 100.64.0.0/10

inet.0: 563509 destinations, 1528595 routes (561239 active, 0 holddown,
3898 hidden)
+ = Active Route, - = Last Active, * = Both

100.100.1.0/24     *[BGP/170] 2d 14:46:05, MED 100, localpref 100
                     AS path: 5580 9498 9730 I, validation-state:
unverified
                   > to 78.152.54.166 via ge-2/0/0.0

My guess is someone leaking an internal route. It's not uncommon to see people using random IPv4 space for internal purposes. Ranges such as
100.100.x.0/24 or 20.20.x.0/24 are often mis-used in this way.

It also looks like at least one of their upsteams is not filtering out any advertisements from 100.64/10.

jms


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