[Dshield] Scanning from

Samantha Fetter sama at snowplow.org
Fri Sep 26 21:01:40 GMT 2003

Newer Cisco IOS versions are using 10/8's for internal interfaces.  I
don't have more details handy, but if you go to Cisco.com I'm sure you
could find something on it (or even [insert your favorite search engine

Have a great weekend,

> FYI, Comcast (previously AT&T) is using the 10/8 block for some kind of
> internal network and this address shows up in traceroute replies from their
> routers and from their DHCP relays. This prevents customers from using ingress
> filtering for these netblocks if they want to use traceroute or DHCP (and they
> must use the latter).
> Here's the first few entries for a traceroute to our favorite service:
> traceroute to dshield.org (, 30 hops max, 38 byte packets
>  1 (  17.699 ms  13.924 ms  12.223 ms
>  2 (  15.083 ms  9.119 ms  8.098 ms
>  3 (  8.664 ms  8.435 ms  9.344 ms

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