Re: Slow connection time - turning off reverse DNS lookup

Hi Felipe,

apart from deconfiguring reverse lookup for every
client side instance using DNS I would rather try
to understand what's going on. Look into the client
system logs and DNS logs, as well as looking into
the DNS network traffic.

If the IP address migration "just" occured, maybe
there's a caching issue on the server side. Or all
of a sudden clients try UDP first which fails for
some strange reason, then TCP? Or whatever....

On the client side you could as well use nscd to cache
DNS entries. However it might be also a good idea
to restart it, if you changed DNS on the server
side, if you have NSCD it running already.

HTH,

Dirk

Am 10/21/2011 03:32 PM, schrieb Felipe Rechia:
> Hello!
> 
> 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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