Subject: Re: [vserver] Understanding localhost
From: "John A. Sullivan III" <jsullivan@opensourcedevel.com>
Date: Fri, 01 May 2009 18:05:15 -0400

On Fri, 2009-05-01 at 23:34 +0200, Herbert Poetzl wrote:
> On Fri, May 01, 2009 at 04:48:12AM -0400, John A. Sullivan III wrote:
> > Hello, all.  I'd like to confirm that I understand the way vserver 2.3
> > is handling localhost and the loopback address.
> 
> > Am I correct to understand that, unlike earlier version, the default
> > kernel compilation makes it safe to use 127.0.0.1 on a guest? That is,
> > each one is uniquely mapped and does not interfere with the host
> > listening in 127.0.0.1? We can thus set our /etc/hosts files to use:
> > 127.0.0.1 localhost localhost.localdomain etc . . .?
> 
> > However, is it also true that daemon bindings to localhost will still be
> > made to the address in /etc/vservers/<guest>/interfaces/0 and will not
> > include 127.0.0.1 unless explicitly bound?
> 
> > I ask because we were delighted to realize we could simplify our zimbra
> > installation by leaving /etc/hosts at 127.0.0.1 for localhost.  We then
> > started retrofitting our other servers to do the same.  Some of our
> > servers communicate with sshd on 127.0.0.1.  We had changed the
> > configuration files to bind them to the non-loopback address, e.g.,
> > 192.168.1.10 because of our old understanding of 127.0.0.1.  We also
> > changed sshd_config by removing the ListenAddress 192.168.1.10 so that
> > it goes back to the default of binding to all interfaces.
> 
> > This broke those applications.  When we do a netstat -tln on the vserver
> > guests, it shows sshd listening only on 192.168.1.10 (as an example) and
> > not 0.0.0.0.  
> 
> if you disable the single IP special casing, this
> will change to the expected behaviour ...
Sorry to be showing my ignorance again but what is "single IP special
casing" that I should be disabling? Thanks - John
> > -- 
> > John A. Sullivan III
> > Open Source Development Corporation
> > +1 207-985-7880
> > jsullivan@opensourcedevel.com
> > 
> > http://www.spiritualoutreach.com
> > Making Christianity intelligible to secular society
-- 
John A. Sullivan III
Open Source Development Corporation
+1 207-985-7880
jsullivan@opensourcedevel.com

http://www.spiritualoutreach.com
Making Christianity intelligible to secular society