In message <200907171319.n6hdjs31003...@dc.cis.okstate.edu>, Martin McCormick writes: > What does bind9.5.1 do when there is an Internet issue and we > loose all root name servers? > > The bind9.3.x we had been running always began producing > tons of lines saying that there were no more recursive clients. I > had written a program that looked for the time stamp when the > mess starts and then for the time stamp of the last distress > call and we called that an outage since bind certainly wasn't > happy. > > We had a very brief outage on the day we switched to > bind9.5.1 and I saw nothing remarkable in the named.log file > during the period where we lost all roots. Either bind9.5.1 > doesn't produce this message or the hit just didn't last long > enough for all the recursive slots to fill up. > > We do allow recursion from within our network but > disallow it for 3RD parties. > > Bind is an excellent place to take the pulse of one's > whole network since it is so closely tied to everything else. > > Here is an actual example of the message we look for: > > 08-Jul-2009 08:38:20.296 client 139.78.102.224#53631: > no more recursive clients: quota reached > > Martin McCormick WB5AGZ Stillwater, OK > Systems Engineer > OSU Information Technology Department Telecommunications Services Group > _______________________________________________ > bind-users mailing list > bind-users@lists.isc.org > https://lists.isc.org/mailman/listinfo/bind-users
BIND 9.5.1 does a better job of shedding load when the nameservers for a query are unreachable than 9.3.x does. BIND 9.5.1 also detects duplicate queries and drops them, BIND 9.3.x doesn't. Both of these will help prevent the recursive quota being reached. BIND 9.5.1 will only allow so many queries for a given <qname,qtype,qclass> to queue, after that it will just drop new queries (servfail TCP). The pushes the queuing back into the clients. The amount of queries auto tunes and ranges between 10 and 100 clients per query in a default configuration. Mark -- Mark Andrews, ISC 1 Seymour St., Dundas Valley, NSW 2117, Australia PHONE: +61 2 9871 4742 INTERNET: ma...@isc.org _______________________________________________ bind-users mailing list bind-users@lists.isc.org https://lists.isc.org/mailman/listinfo/bind-users