----- Original Message ---- > From: Mark Andrews <[email protected]> > To: Fr34k <[email protected]> > Cc: Bindlist <[email protected]> > Sent: Mon, April 4, 2011 9:02:35 PM > Subject: Re: BIND 9.7 behavior - lack of response causes > > > What do you have lame-ttl set to?
I don't. That is, I don't have lame-ttl explicitly listed in my named.conf. > > In message <[email protected]>, Fr34k writes: > > Hello, > > > > Given: BIND 9.7.2-P2 on Solaris 10. > > > > For about an hour, I had a network event where a caching DNS server could >not > > > > get recursive queries back from authoritative DNS servers on the Internet. > > > > Obviously, this is a problem. > > > > Moreover, the authority for our most popular hostnames have set very low >TTLs > > > > (less than a minute), so nothing in cache for the server to call upon > > during > > > this hour long event. > > > > Yuck. > > > > A snoop of port 53 traffic at the time shows client PCs requested hostname > > resolution -- as they would normally do. > > > > Now, for the interesting part. > > > > >From the same snoop of traffic, the caching DNS server did not send ANY >resp > > onse > > back to these PC clients for these low TTL popular hostnames. > > > > Keep in mind that I did snoop until *after* the event started. > > > > So, it may be the case that some BIND mechanism was behaving appropriate > > for > > > queries which it could not act upon. I can appreciate that BIND makes >decisi > > ons > > with network performance in mind. > > > > In my attempts to understand negative caching, Sections 7.1 and 7.2 of RFC >23 > > 08 > > list Server Failure and Dead / Unreachable Server as "(OPTIONAL)" utilities. > > > > Bind 9.7 ARM says that "the server stores negative answers" for (default) > > 3 > > hours; however, I'm not sure what the expected BIND behavior is. > > > > Would some mechanism, such has max-ncache-ttl or clients-per-query, be > > responsible for this lack of return traffic? > > > > Anyone have ideas to share? > > > > Thank you. > > > > _______________________________________________ > > bind-users mailing list > > [email protected] > > https://lists.isc.org/mailman/listinfo/bind-users > -- > Mark Andrews, ISC > 1 Seymour St., Dundas Valley, NSW 2117, Australia > PHONE: +61 2 9871 4742 INTERNET: [email protected] > _______________________________________________ bind-users mailing list [email protected] https://lists.isc.org/mailman/listinfo/bind-users
