Public bug reported:

Binary package hint: avahi-daemon

I encountered this problem on a machine that is integrated into our work
network. I performed a dist-upgrade to Feisty on my desktop and all went
well. I've noticed recently that any dns based work seemed to take a
significantly longer time then normal.

My system is getting dns information on our company internal systems
from two dns servers. Previously, if I tried to establish an ssh
connection with another system I could generally expect the connection
in under 3 secs.

After the dist-upgrade the time went from under 3 seconds to
approximately 25 seconds. After searching around the system I found an
entry in /etc/nsswitch.conf that cause me a little concern. The line in
question is:

   hosts:          files mdns4_minimal [NOTFOUND=return] dns mdns4

I looked around a bit and it seems that the references to mdns are
really talking about communication with the Avahi mDNS/DNS-SD daemon.
Since this looks to be a part of a zeroconf configuration I wasn't
expecting too much in my current environment, as we really only have
three Mac's.

What concerned me is the idea that if we hit files with no answer there
is a delay while we hit the other options until we hit dns, which is
where the information I seek existed.

For an experiment I tried two separate tests. The first changed the line
to looks like:

    hosts:          files dns mdns4_minimal [NOTFOUND=return] mdns

The change should have improved the time, but I was still looking at
approximately 23 seconds to return a command prompt on the destination
machine.

Finally, I change the entry to simply:

    hosts:          files dns

After this change I was again receiving the destination command prompt
in under 3 seconds. I don't know if simply changing the file will
correct the problem long-term or not. Seems to help me, but might be the
way to go for most Ubuntu users.

ProblemType: Bug
Architecture: i386
Date: Thu Mar 22 18:10:54 2007
DistroRelease: Ubuntu 7.04
Uname: Linux samdesk 2.6.20-12-generic #2 SMP Wed Mar 21 20:55:46 UTC 2007 i686 
GNU/Linux

** Affects: avahi (Ubuntu)
     Importance: Undecided
         Status: Unconfirmed

-- 
mdns listed in nsswitch.conf causes excessive time  for dns lookups
https://launchpad.net/bugs/94940

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