Date: Tue, 22 May 2001 14:35:52 -0500 (CDT) From: Nick Rogness <nick@rogness.net> To: Mark Drayton <mark.drayton@4thwave.co.uk> Cc: freebsd-isp@FreeBSD.ORG Subject: Re: Resolving DNS setup Message-ID: <Pine.BSF.4.21.0105221426060.91693-100000@cody.jharris.com> In-Reply-To: <20010522185407.A30604@tethys.valhalla.net>
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On Tue, 22 May 2001, Mark Drayton wrote: > Recently I set up a caching only nameserver at work which all our > office machines, servers and dialup customers use for resolution > instead of our two authoritative nameservers. A few days ago our > internet connection went down, meaning that the caching nameserver > couldn't get to the root nameservers and therefore couldn't resolve > anything it didn't have cached. As it couldn't get to the root servers > it also couldn't answer any queries for zones that we are > authoritative for (even though the authoritative namesevers are on the > same network). > > The end result of this was that customers who dialled into us couldn't > see our site or pick up their mail as the caching nameserver wouldn't > resolve the hostnames of the web/mail servers. > > Obviously this is a Bad Thing and I'd like to sort it out, especially > as I'm going to add another caching nameserver in the near future. > What would be the best way of fixing this? My thoughts so far are: One solution maybe to add your authoritative name servers as forwarders in your caching only server config. > > a) make the caching nameserver a slave for all the domains held on our > authoritative nameservers That would work too. > > b) define all our domains as stub zones on the caching nameserver > > Another problem with the caching nameserver is it's very slow to pick > up *new* RRs on our authoritative servers (I know I need to wait for > the TTL to expire on changed records). Will the caching nameserver > wait for the TTL of the zone to expire before it asks the > authoritative servers, *even when it has no cached answer to the > query*? > No, caching nameserver should get the info directly if it is not cached locally, plain and simple. The TTL for that record on the caching nameserver will take affect after it has been cached locally on the caching nameserver. Nick Rogness <nick@rogness.net> - Keep on Routing in a Free World... "FreeBSD: The Power to Serve!" To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-isp" in the body of the message
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