[PLUG] DNS issues

Rich Burroughs rich at paranoid.org
Wed May 11 22:32:18 UTC 2005


On Wed, May 11, 2005 2:38 pm, Ovid said:
> Thanks.  The "host google.com $DNSSERVER" always seems to return
> immediately as does the "ping -c1 google.com".  However, the traceroute
> on both my iBook and the FC2 box does this (from the Ibook):
>
> 13  vlan201-msr1.dcn.yahoo.com (216.115.96.163)  116.508 ms  134.078 ms
> vlan221-msr2.dcn.yahoo.com (216.115.96.167)  118.578 ms
> 14  ge2-2.bas2-m.dcn.yahoo.com (216.109.120.153)  137.382 ms
> ge3-1.bas2-m.dcn.yahoo.com (216.109.120.146)  178.671 ms
> ge6-1.bas2-m.dcn.yahoo.com (216.109.120.221)  104.433 ms
> 15  * * *
> 16  * * *

It sounds like you have your problem resolved, but FYI, traceroutes are
unfortunately less useful than they used to be. In the old days you could
traceroute pretty much anywhere, but now many people filter ICMP at their
firewalls/routers. They do it to prevent ICMP DoS attacks, and also to
prevent people from gaining more information about their networks.

Traceroute is still pretty handy for looking at things like the path you
are taking through your ISP and then the Internet backbone, but once you
get to the network on the other end it may not tell you much more (which
seems to be what's happening in the example above).


Rich





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