[Users] Suggestion for a new parameter: PRIMARY_IP

[Marcin Owsiany]

On Wed, Jan 07, 2009 at 12:41:39PM +0100, Dietmar Maurer wrote:
> > Oh, just about anything that does: socket(); connect(); (without a
> > bind() in between), for example default usage of wget, telnet, ssh..
> > any
> > TCP client really.
> 
> If you have a server using several IP addresses, the client IP address
> used by tcp client is undefined.

Yes, it seems so, in the general case. However I would be comfortable
enough with the current-Linux-specific behaviour.

> But what application depends on the client IP used?

Anything that needs to connect out to the public Internet. This is
because when it picks an RFC1918 address, the connection cannot be
established when there is no NAT employed.

> Anyways, usually you can specify the bind address:
> 
> wget: --bind-address=ADDRESS 
> telnet: -b address

Yes, but not in all cases.

Look, I do know there are other ways around this, including carefully
configuring the applications, NATing, proxying, even site-specific
tweaking the OpenVZ setup scripts to do some crazy mangling my of
interfaces.

However all of these have downsides, and the option I suggested seemed
to me to give the most "bang for the buck".

-- 
Marcin Owsiany <marcin at owsiany.pl>              http://marcin.owsiany.pl/
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