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Re: ICMP weirdness

  • From: Crist Clark
  • Date: Mon Oct 18 17:08:13 2004

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.)

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@globalstar.com
Globalstar Communications                                (408) 933-4387

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