[CentOS] dhcpd options (related)

Thu Mar 21 18:54:17 UTC 2013
m.roth at 5-cent.us <m.roth at 5-cent.us>

m.roth at 5-cent.us wrote:
> m.roth at 5-cent.us wrote:
>> A few weeks ago, suddenly, reading news at lunch, I could not get to
>> nytimes.com. I could ping it, and nslookup it, and if I put the IP
>> address in place of the name, it was fine.
>>
>> After *much* back and forth over a ticket I put in, over the last week
>> or so, our group figured it out: It *seemed* to be related to IPv6, and
>> there's only *some* few sites, such as the Times, and Orbits, and one or
>> two others I found, while, say, the Washington Post, or Huffpo, etc,
>> were fine; and I could make it work by putting IPV6INIT="no" in ifcfg-eth0
>> and restarting the network, but another admin got it nailed, we *think*:
>> apparently the M$-based DNS resolver's sending back extended DNS
>> packets, and we gag. tcpdump saw us asking for an A record, then an
AAAA record, then using search....
>>
>> But putting the *very* counterintuitive option edns0 in
>> /etc/resolv.conf,
>> it works instantly, no caching, no nuthin'. Taking that out breaks it
>> again.
>>
Hate to follow myself up, but here's another question: is it possible that
th3e IPV6INIT="yes" in ifcfg-eth0 sets the networking into a state where
it's sending *out* an edns query record, but doesn't understand the reply
edns record, until we tell it to with option edns0?

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