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Date:	Fri, 13 Jun 2014 10:05:42 +0000
From:	David Laight <David.Laight@...LAB.COM>
To:	'Geert Uytterhoeven' <>
CC:	Tom Herbert <>,
	"David S. Miller" <>,
	Linux-Next <>,
	Linux-sh list <>,
	"" <>,
	"" <>
Subject: RE: [-next] Regression: ssh log in slowdown

From: Geert Uytterhoeven
> Hi David,
> On Fri, Jun 13, 2014 at 10:49 AM, David Laight <> wrote:
> > From: Of Geert Uytterhoeven
> > ...
> >> Note that I'm also using NFS root, which doesn't seem to be affected.
> >> I can happily run "ls -R /" on the serial console during the 10 s delay in ssh.
> >
> > Are you sure that the delay during ssh login isn't just
> > a reverse DNS timeout?
> Indeed, the ssh server sends a reverse DNS request twice, with 5s in between:
> Interestingly, I don't see the forward DNS request after that, which
> does happen in the good case.

The forwards request is probably just copying some strange code from 'rshd'
that tried to verify the reverse lookup by doing a forwards lookup on the
That in itself used to cause us grief.
The RDNS would (correctly) generate, since the 'domain'
in etc/resolv.conf was the forwards lookup first tried then
one of which always timed out :-(
(When the 'search' command was added we could avoid the request that
timed out.)


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