IPNAT seems to affect network performance? of jails on lo0 ( - why?

Christopher J. Ruwe cjr at cruwe.de
Tue Jun 26 14:58:50 UTC 2012

On Mon, 25 Jun 2012 18:23:56 -0400
Robert Huff <roberthuff at rcn.com> wrote:

> Christopher J. Ruwe writes:
> >  On a KVM virtualized host, I run FreeBSD 8.3-RELEASE-p3 and some
> >  qjails, 8.3-RELEASE. The jails are connected all via lo0 on
> >
> >  
> >  While by the large working as expected, I have noticed one
> >  pecularity I have failed to pinpoint: When launching processes
> >  with some network interaction, like sshing into one of the jails
> >  from the platform or launching emacs, the command spends ages (
> >  ~(1-2) minutes) idling?  (nothing happens) before becoming
> >  interactive.
> 	If the number is very close to 90 seconds, my first guess
> would be you have a DNS problem.
> 					Robert Huff
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Thanks for the hint. It was DNS ... I have copied a resolv.conf into the
jails for future use, but did not enable NAT from the start. 

The issue disappeared when I commented out the nameserver entries and
switched NAT off again, i.e., I could login using ssh in a matter of
seconds, not minutes.

Now to the followup: Why does ssh and emacs! require DNS for entirely local
connections or just to be started?

Anyway, thanks for that hint, cheers,
TZ: GMT + 2h
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