My DNS not always available on the web

[Dan Winchester]

Thanks Barry.

So, can a domain contain its own authorative nameservers? In other words could I
use ns1.funktion.co.uk and ns2.funktion.co.uk as the name servers for
funktion.co.uk? If so then I could at least eliminate the bb-online.net stage.

Barry Margolin wrote:

> In article <7o6gtu$85t$1 at nnrp1.deja.com>,
> Dan Winchester  <andy.stowell at virgin.net> wrote:
> >Hi,
> >
> >Everyday I seem to get two or three emails from people saying that when
> >they try and access my site (http://www.freelancers.net) they get a DNS
> >error. Both DNS servers are based here in my office (as is the
> >webserver) so I know they are always up as I never have to restart them.
> >
> >Ok, so what I generally do is try and track down what DNS they would be
> >using based on their email address and query it for my domain. More
> >often than not my query seems to time out with a 'no DNS for host
> >freelancers.net' type message. But then if I run the same query again it
> >resolves immediately.
> >
> >So, is the problem here that my DNS is just too slow? If so how can I
> >speed it up? Here are the name servers:
>
> I think the problem may be that there are many levels of indirection
> involved.  Here's a typical scenario when the user's server doesn't have
> anything related to your domain or ISP in its cache (I'll assume that it
> does have common TLD and country domain info cached, since that's typical).
>
> It queries a root/gtld server for www.freelancers.net.  The server returns
> a referral:
>
> FREELANCERS.net.        172800  NS      NS1.FUNKTION.CO.UK.
> FREELANCERS.net.        172800  NS      NS2.FUNKTION.CO.UK.
>
> Now it needs to look up ns1.funktion.co.uk or ns2.funktion.co.uk.  Most
> likely it will have the .CO.UK NS records in its cache (per my assumption
> above), so it doesn't need to start at the root servers again.  It will
> pick one of the .CO.UK servers and query it.  This will return:
>
> funktion.co.uk. 14400   NS      ns1.bb-online.net.
> funktion.co.uk. 14400   NS      ns2.bb-online.net.
>
> Now it has to look up ns1.bb-online.net or ns2.bb-online.net.  It will
> query one of the root/gtld servers.  This time it gets an answer rather
> than a referral (I'm not sure why -- these don't seem to be necessary glue
> records):
>
> ns1.bb-online.net.      172800  A       194.168.163.59
>
> Now it queries this server and gets:
>
> ns1.funktion.co.uk.     86400   A       212.19.75.168
>
> and then it finally gets to send the original query to this server, which
> responds with the answer.
>
> All these queries take time, and if it has to go through all of them the
> querier may time out, especially if there's some network congestion that
> causes packets to be lost, requiring one or more to be retried (from my
> desktop in Massachusetts most of these queries took 100-200 ms, so the
> total time should be around .5-.7 seconds if there are no errors).
>
> --
> Barry Margolin, barmar at bbnplanet.com
> GTE Internetworking, Powered by BBN, Burlington, MA
> *** DON'T SEND TECHNICAL QUESTIONS DIRECTLY TO ME, post them to newsgroups.
> Please DON'T copy followups to me -- I'll assume it wasn't posted to the group.

--
Dan Winchester

http://dan.freelancers.net
mailto:dan at freelancers.net

http://www.freelancers.net