Subject: Re: [vserver] Loopback issues
From: Philippe Teuwen <phil@teuwen.org>
Date: Thu, 23 Aug 2007 08:48:40 +0200


> Thanks, but I don't want to create a private network between the
> vservers, rather, I want to assign some ip addresses to one of the
> vservers that none of the other vserver will send to directly (not even
> via the host). I can't see how I can do this.
>   
private adresses not visible even by the host, that's really the problem...
> The scenario is this:
>
> I have a load balanacer (lb) sitting in front of some servers, one of
> which is a vserver host. One of the load balanced services is mail, and
> it has the virtual IP of 4.3.2.1 on lb. The vserver host contains 2
> vservers: one for web with ip 1.2.3.4 and one for mail with ip 1.2.3.5.
> There is a separate mail server with ip 1.2.3.6. Mail traffic coming to
> the ip 4.3.2.1 gets distributed between 1.2.3.5 and 1.2.4.6. These
> servers need to have a hidden interface with the ip 4.3.2.1 so that they
> accept the packets forwarded by lb.
>   
How this distribution is done when you've physical distinct servers?
lb forwards packets to ip 4.3.2.1 and mac of 1.2.3.x? even if lb has 
itself such 4.3.2.1 ip?

Another idea:
Could you do load balancing via ports rather than macs?

lb, A and B have all the same IP 4.3.2.1
vservers A and B run your mail service respectively on ports 2501 and 2502.
lb accepts external packets on port 25 and forward them to "itself" on 
port 2501 or 2502.

Phil