Date: Sat, 19 Jul 1997 12:37:57 +0000 From: "Ronald E. Eakins, Sr." <reakins@nms.net> To: isp@FreeBSD.ORG Subject: Re: DNS "slow" Message-ID: <199707191942.MAA02575@ns1.nms.net> In-Reply-To: <199707182241.PAA20858@hub.freebsd.org>
next in thread | previous in thread | raw e-mail | index | archive | help
> From: "Patrick Burm" <patb@commlitho.com> > To: "Robert Shady" <rls@mail.id.net> > Cc: <isp@FreeBSD.ORG> > Subject: Re: DNS "slow" > Date: Fri, 18 Jul 1997 15:42:04 -0700 > > > Reason I'm asking...some of my users are getting > > > "error getting address for xxx.xxxx.xxx" for my > > > own mail server! they can try again a second time > > > and everything is fine. The ones who complain the > > > most are the people with 14.4s. > > I have seen this problem under the following conditions: You have a Primary and a Secondary server and the clients point at the Secondary server first. Since the secondary server has to obtain info from the primary, it goes to get the name from the primary, but by then, the client has timed out. Now the client tries again and this time the secondary has the address in it's cache so the lookup works. OR: Your primary DNS is getting it's names from some server higher up the tree which is a secondary server. As and example - U.S. West uses multiple DNS Servers of which only one is the primary. And of course they don't want everyone under them to point at one machine so one of their secondaries is what your primary points at. Same problem occurs, the machine your primary is pointing at has to go resolve the name and guess what, the client times out. Don't know how you can really fix that one. Check with whoever it is that is the next guy up the DNS tree supplying you. > > They could be timing out. Have you had any problems > > looking up dns's locally (Aside from below). There are lots of other issues here with DNS lookups. How you have configured the DNS can adversely effect performance. Those first few lines regarding timeouts are lots more important than people give them credit for. My source for DNS questions is here: http://www.acmebw.com/askmr.htm I would suggest you try this link. Ronald E. Eakins, Sr. Network Engineer Network Management Solutions, Inc. www.nms.net reakins@nms.net ---------------------------------- Ronald E. Eakins, Sr. Network Engineer Network Management Solutions, Inc.
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?199707191942.MAA02575>