Sometimes users get host unknown

[Andrew Watkins]

Hi,

We have had an ongoing problem that some people (over the world) that 
they can not access our web server, since they do not get an IP address.

I have tested from my home ISP (away from work) and am unable to get the 
same errors. I have tested the DNS from a few web sites www.dnsstuff.com 
, etc and can not pin point any major problem

Our webserver has many addresses
www.lkl.ac.uk
www.lonklab.ac.uk
www.londonknowledge.ac.uk


The last report we had from a user was: dig +trace +qr www.lkl.ac.uk

; <<>> DiG 9.2.1 <<>> +trace +qr www.lkl.ac.uk
;; global options:  printcmd
.                       47891   IN      NS      c.root-servers.net.
.                       47891   IN      NS      b.root-servers.net.
;; Received 356 bytes from 165.225.198.2#53(165.225.198.2) in 5 ms

uk.                     172800  IN      NS      NS1.NIC.uk.
uk.                     172800  IN      NS      NSD.NIC.uk.
;; Received 493 bytes from 192.33.4.12#53(c.root-servers.net) in 48 ms

ac.uk.                  172800  IN      NS      ns1.cs.ucl.ac.uk.
ac.uk.                  172800  IN      NS      ns2.ja.net.
ac.uk.                  172800  IN      NS      ns3.ja.net.
ac.uk.                  172800  IN      NS      ns4.ja.net.
ac.uk.                  172800  IN      NS      sunic.sunet.se.
ac.uk.                  172800  IN      NS      ws-fra1.win-ip.dfn.de.
ac.uk.                  172800  IN      NS      ns.uu.net.
ac.uk.                  172800  IN      NS      ns0.ja.net.
;; Received 233 bytes from 195.66.240.130#53(NS1.NIC.uk) in 129 ms

lkl.ac.uk.              86400   IN      NS      ns1.lonklab.ac.uk.
lkl.ac.uk.              86400   IN      NS      mail1.ccs.bbk.ac.uk.
;; Received 101 bytes from 128.16.5.32#53(ns1.cs.ucl.ac.uk) in 150 ms

dig: Couldn't find server 'ns1.lonklab.ac.uk': Name or service not known


Any pointers?


Thanks in advance,

Andrew Watkins
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Unix Administrator                           tel: 020-7631 6720
Computer Science Department                  fax: 020-7631 6727
Birkbeck College (University of London)
Malet Street
London                                       e-mail: andrew at dcs.bbk.ac.uk
WC1E 7HX 
http://www.dcs.bbk.ac.uk/~andrew
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