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Re: ICMP weirdness
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] 3 126.96.36.199 (188.8.131.52) 17.315 ms 17.378 ms 17.492 ms 4 184.108.40.206 (220.127.116.11) 33.548 ms 23.702 ms 13.066 ms 5 18.104.22.168 (22.214.171.124) 21.554 ms 18.118 ms 18.589 ms 6 gbr2-p50.sffca.ip.att.net (126.96.36.199) 23.677 ms 31.973 ms 18.647 ms 7 tbr1-p012702.sffca.ip.att.net (188.8.131.52) 24.447 ms 19.266 ms 19.036 ms 8 tbr1-cl2.sl9mo.ip.att.net (184.108.40.206) 73.801 ms 66.745 ms 71.541 ms 9 gbr2-p10.sl9mo.ip.att.net (220.127.116.11) 68.524 ms 62.157 ms 66.172 ms 10 gar1-p370.sl9mo.ip.att.net (18.104.22.168) 68.568 ms 65.325 ms 62.455 ms 11 12-220-0-69.client.insightBB.com (22.214.171.124) 93.072 ms 98.102 ms 91.132 ms 12 12-220-7-198.client.insightBB.com (126.96.36.199) 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:
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