Dnia 1-07-2009 o godz. 19:02 Kevin Darcy napisał(a): > TPZ wrote: > > Are there any options for Bind to configure timeout for DNS requests? > > > > > > > Short answer: not as far as I know. > > Hopefully you understand that it's the DNS clients, and not BIND itself, > that implement the main timeout/retry strategy for a DNS query > transaction. Send a request, if it times out, try another resolver in > the resolver list, or retry the request. The main determinant of whether > a request succeeds or fails, therefore, in the face of slow or > unavailable upstream nameservers, is the client resolver's > configuration, not BIND's. The applications which call the resolver > routines on those clients, may also have their own timeout values, which > can sometimes be significantly shorter than what is set in the client > resolver. Therefore they will timeout the lookup request before the > client resolver would have abandoned it. > > BIND itself will time out and fail over quickly -- on the order of > milliseconds -- between the nameservers it talks to. It will also keep > track, in its cache, of what nameservers are responding slowly, or which > are giving invalid answers, and de-prioritize or avoid nameservers in > those respective categories. So, in practical terms, it is "self-tuning" > over time, and in a way that is far more sophisticated than setting a > single "timeout" value could ever hope to accomplish. > > - Kevin > > _______________________________________________ > bind-users mailing list > bind-users@lists.isc.org > https://lists.isc.org/mailman/listinfo/bind-users
Thank you for explain. I experienced some problems with i.e. SSH, because there is an option set by default #UseDNS yes. And when DNS is not available (ie via /etc/resolv.conf) it is about 30 seconds timeout. Even if you connect like this "ssh u...@192.168.100.12" (without DNS domain name) application trying contact DNS. Are you agree with me? _______________________________________________ bind-users mailing list bind-users@lists.isc.org https://lists.isc.org/mailman/listinfo/bind-users
