[PLUG] DNS Resolution Problems - 5 second delay

AthlonRob AthlonRob at axpr.net
Wed Oct 8 16:27:01 UTC 2003


On Wed, 2003-10-08 at 16:08, Steve Bonds wrote:

> Yep, you'll see little quantii of time spent when DNS times out because of
> packet loss.  This depends on the number of DNS servers listed in your
> resolv.conf.  The default timeout in /usr/include/resolv.h is (big
> surprise) 5 seconds.

Thank you for all the tcpdump info and other info..

I don't have the packet dropping problem resolved, but can live with it
now.

Since my firewall redirects all dport=53 packets back to my DNS server,
I just set up resolv.conf to point to five bogus DNS servers.  Now the
maximum before I get a response is 1.020 seconds.

It doesn't quite make statistical sense, but it cut the time down, so
things are in good enough shape.

I'll take a look at netperf and tcptrace as my next project, I think. 
:-)

Thanks for the help!

Rob





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