Dhcpd Options

Home » CentOS » Dhcpd Options
CentOS 1 Comment

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.

My question: it *appears* that we could add option edns0
to dhcpd.conf on the server, and it would fix it for everyone on our subnet.

Have I misunderstood what I’m reading in the manpages?


One thought on - Dhcpd Options