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We monitor our website's homepage using websitepulse.com. They provide a detailed breakdown of the steps for fully downloading our homepage.

I am seeing somewhat high variance in DNS lookup time. It can take anywhere between 200ms to 2 seconds.

Our domain has three nameservers:

mimas.rh.com.tr
janus.radore.com
titan.radore.com

I am wondering if one of these nameservers is performing poorly.

How do I go about checking this? I figure, if I remove the bad performing nameserver from our domain information, I can reduce the dns lookup variance.

Thanks, Haluk

XXXXXXXXXXX UPDATE: Is this a valid way of checking nameserver response times?

#dig ns sample.com @mimas.rh.com.tr
#dig ns sample.com @janus.radore.com
#dig ns sample.com @titan.radore.com

These commands output query response times. Is this what I am looking for?

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3 Answers 3

up vote 0 down vote accepted

You should check the nameservers websitepulse uses, because the delay in dns lookup could come from here.

Do their dns cache the results, or just forward to yours ?

A good idea would be to monitor your own nameservers in addition to the website, in order to check if there are any slowdowns.

edit:

Yes, dig indicates how long it was to execute the query. But I was thinking about something more powerful, automatic, like nagios/munin/cacti...

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Okay. I will ask your question to the monitoring company. In the meantime. I have edited my question above, let me know if my new question makes sense. –  Haluk Nov 21 '10 at 20:25

Check out the namebench tool: http://code.google.com/p/namebench/

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Yes, those dig commands are a reasonable way to check it, assuming that your network doesn't intercept the outgoing queries or anything like that. Probably you should run similar commands from machines at various different points on the net.

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