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RE: Slow connection time - turning off reverse DNS lookup

Alexander.Stade Alexander.Stade@vattenfall.com
Fri, 21 Oct 2011 14:26:29 GMT

Without having the slightest clue about your setup aside from what you've told me, what type of system(s) are we dealing with? For instance, in Solaris you can define search orders in /etc/nsswitch.conf for hosts databases:

hosts: files dns

Then add the appropriate entries to your /etc/hosts file and things should speed up a bit.

As an aside, it doesn't make much sense to me that you'd get a 45 sec timeout if a DNS server is responding with an NXDOMAIN error. It seems to me that you're looking for DNS servers that aren't responding. I'd check to see if your DNS server settings are correct prior to trying to alter source code to circumvent this behavior.


From: users-bounces@conserver.com [users-bounces@conserver.com] On Behalf Of Felipe Rechia [feliperechia@gmail.com]
Sent: Friday, October 21, 2011 3:32 PM
To: users@conserver.com
Subject: Slow connection time - turning off reverse DNS lookup


I am currently using conserver to access several serial interfaces
spread out among a few servers. We have a single conserver-server
acting as master, and 6 servers have their serial interfaces
accessible via this star topology.

We've just had an IP address migration and our conserver clients no
longer have proper reverse DNS lookup.

Users are complaining that console now takes a long time to show the
current status (console -u) and also a long time to connect. For
instance, console -u takes 45 seconds to show all the available serial
ports (at most 8 serial ports per server)

Just for comparison purposes, a similar problem was found with SSH,
but it is possible to solve it by disabling the UseDNS parameter in
/etc/ssh/sshd_config file ("UseDNS no") at the server.

Is it possible to turn off reverse DNS lookup on conserver? If so, how
is it done? I have searched for this in the man pages but couldn't
find anything... A workaround is to add all known hosts to each
server's /etc/hosts file, but this is the dumb way of solving it...
Any other ideas?

Thanks in advance for any feedback! And also many thanks for the
conserver app, it is a really useful tool :)

Best Regards
Felipe Rechia
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