ICMP weirdness
Daniel Senie
dts at senie.com
Mon Oct 18 21:38:34 UTC 2004
At 05:02 PM 10/18/2004, Crist Clark wrote:
>Jim Popovitch wrote:
>
>> From Comcast Cable, at my home in Atlanta, I can ping 10.10.1.1....
>>which is pong'ed from a private client network hanging somewhere off of
>>Insight Broadband's network in the North Central part of the US. Why on
>>god's green earth do network operators allow such nonsense as this?
>
>FWIW, I get the same result from Comcast residential coax
>service from Santa Clara, CA using a plain ol' *nix UDP
>traceroute. (This is not ICMP specific.)
Interesting to see who does and doesn't apply bogon filters to their BGP
sessions.
From a Verio space, the packets do not make it past a default-free router.
Good filtering.
From AT&T space, the trace goes all the way to InsightBB, no filtering of
prefixes.
It appears XO does not filter, but that whomever they try to hand the
traffic off to in Dallas does filter.
Comcast (New England) seems to have some level of filtering, but has a
default route loop between Lowell, MA and Needham, MA in their traces. Nice.
Appears level3.net filters properly.
The presence of the route did provide a nice set of data to see whose
networks are implementing filtering.
>raceroute 10.10.1.1
>traceroute to 10.10.1.1 (10.10.1.1), 64 hops max, 44 byte packets
>[snip my internal net]
> 3 12.244.25.145 (12.244.25.145) 17.315 ms 17.378 ms 17.492 ms
> 4 12.244.67.17 (12.244.67.17) 33.548 ms 23.702 ms 13.066 ms
> 5 12.244.72.206 (12.244.72.206) 21.554 ms 18.118 ms 18.589 ms
> 6 gbr2-p50.sffca.ip.att.net (12.123.13.62) 23.677 ms 31.973 ms 18.647 ms
> 7 tbr1-p012702.sffca.ip.att.net (12.122.11.69) 24.447 ms 19.266
> ms 19.036 ms
> 8 tbr1-cl2.sl9mo.ip.att.net (12.122.10.41) 73.801 ms 66.745 ms 71.541 ms
> 9 gbr2-p10.sl9mo.ip.att.net (12.122.11.102) 68.524 ms 62.157
> ms 66.172 ms
>10 gar1-p370.sl9mo.ip.att.net (12.123.24.213) 68.568 ms 65.325
>ms 62.455 ms
>11 12-220-0-69.client.insightBB.com (12.220.0.69) 93.072 ms 98.102
>ms 91.132 ms
>12 12-220-7-198.client.insightBB.com (12.220.7.198) 88.131 ms 83.943
>ms 85.713 ms
>13 10.10.1.1 (10.10.1.1) 159.507 ms 101.956 ms 95.575 ms
>
>I know that Comcast (formerly AT&T BB) uses the 10-net internally
>on their transit networks so they can't just blackhole the stuff.
>Insight's ISP is AT&T (now Comcast?). Looking quickly at the AT&T
>looking glass, Insight appears to not have its own AS. RFC1918
>successfully crossing between ASes would be a Very Bad Thing.
>However, it looks like it is completely within AT&T here. Not a
>Good Thing, but not the end of the world. For all I know,
>10.10.1.1 might be AT&T equipment using their internal 10-net.
>
>
>>Traceroute -I 10.10.1.1 produces the following:
>>traceroute to 10.10.1.1 (10.10.1.1), 30 hops max, 38 byte packets
>> 1 10.238.10.1 (10.238.10.1) 29.089 ms 25.387 ms 28.574 ms
>> 2 66.56.22.66 (66.56.22.66) 30.923 ms 31.305 ms 33.142 ms
>> 3 66.56.22.70 (66.56.22.70) 35.945 ms 35.874 ms 36.832 ms
>> 4 c-66-56-23-38.atl.client2.attbi.com (66.56.23.38) 34.740 ms 35.041
>>ms 37.537 ms
>> 5 12.118.184.41 (12.118.184.41) 41.967 ms 45.584 ms 43.997 ms
>> 6 gbr2-p70.attga.ip.att.net (12.123.21.6) 44.988 ms 44.706 ms 43.033 ms
>> 7 tbr2-p013602.attga.ip.att.net (12.122.12.37) 49.353 ms 44.010 ms
>> 45.244 ms
>> 8 12.122.10.138 (12.122.10.138) 62.244 ms 62.269 ms 62.148 ms
>> 9 gbr1-p40.sl9mo.ip.att.net (12.122.11.114) 60.922 ms 67.005 ms
>> 60.264 ms
>>10 gar1-p360.sl9mo.ip.att.net (12.123.24.209) 59.572 ms 64.013 ms
>>60.198 ms
>>11 12-220-0-69.client.insightBB.com (12.220.0.69) 77.000 ms 76.050
>>ms 77.926 ms
>>12 12-220-7-198.client.insightBB.com (12.220.7.198) 95.437 ms 80.068
>>ms 84.076 ms
>>13 10.10.1.1 (10.10.1.1) 93.612 ms 97.280 ms 192.994 ms
>>
>
>
>--
>Crist J. Clark crist.clark at globalstar.com
>Globalstar Communications (408) 933-4387
>
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