[thelist] Re: Checking DNS of an ISP

Jeana Bucholz diva at divadesigngroup.com
Fri Mar 28 09:59:24 CST 2003

> Date: Thu, 27 Mar 2003 17:16:54 -0600
> From: Gustavo Arizpe <listas at areaestrategica.com>
> To: "thelist at lists.evolt.org.uk" <thelist at lists.evolt.org>
> Subject: [thelist] Checking DNS of an ISP
> Message-ID: <32CE04B0-60AA-11D7-AAEC-0003931C4202 at areaestrategica.com>
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> Hi, I have a customer who connot see his web site (hosted in a virtual
> hosting server which I resell) in his local network. Outside his local
> network the site loads quickly.
> I believe the problem has to do with his ISP DNS or even his local
> network DNS, but I don't know how to prove that. How could he check
> this in Windows, i.e. how could he verify that his domain name is not
> misconfigured in his local network or his ISP's?
> If he does traceroute all he gets is slight delays, but via http the
> site takes ages to load, so my guess is some local misconfiguration of
> DNS, either in his local network or his ISP.
> Any suggestion will be appreciated.
> Gustavo
> ------------------------------

Hi Gustavo,

Here's a good place to start.  I assume that the customer is probably on a
windows machine.  Have him locate the hosts file on his machine  (usually
C:\Windows\hosts ).  Open the file in notepad and edit it as the example
shows in the file, using the IP address of the virtual server and the
www.domainname.com of the customer's website.  Save the file and then have
him try navigating to the website again.  If the site comes up right away
(or after a refresh), then the configuration problem is either on his local
network or with his ISP's name server.  If it doesn't, then you may need to
check to make sure the domain's DNS has been transfered to the proper IP
address (of your virtual server) with the domain registrar.  It's also
possible, that if the customer had the site previously hosted elsewhere, he
or the network admin has a DNS entry for the site on their local server that
is trying to resolve to a previous address.  These are most likely.  If none
of these things fix the problem, perhaps a call to the customer's ISP to
have them try  resolving the name.  Sometimes there are strange little
reverse DNS lookup issues that occur between ISP's that will cause a site to
work extremely slow or not at all, though this is rare.  Good luck.


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