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Re: [Xen-users] One nic multiple ip's

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Subject: Re: [Xen-users] One nic multiple ip's
From: Simon Hobson <linux@xxxxxxxxxxxxxxxx>
Date: Tue, 25 Aug 2009 23:33:23 +0100
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nomid wrote:
I have one nic and 5 static ip's. i use debian lenny.

How configure dom0 and domU, gets own ip address.

I think what you are asking is :

Your connection is via ethernet and your upstream provider gives you 5 IPs (I'm guessing a /29 subnet). You want to use different IPs for Dom0 and each DomU.

It's very simple, in each device you want to have a public IP, you configure it with the correct subnet mask, one IP from the range provided, and set the default gateway to the upstream providers router address.

Eg, if the IPs provided are from to and the providers router is at, then you might configure Dom0 as :
IP:, netmask, gateway
Your first DomU as :
IP:, netmask, gateway
and so on.

You would of course configure your Dom0 networking in bridge mode.

There are other ways to set things up. Some providers will give you a /29 subnet, but route your traffic over a point-point link with a different /30 subnet. Sticking with the same subnet as above, you'd want to run in routed mode, with an outside interface IP to match the link and an inside interface in your subnet.

Yet another option is via proxy arp.

You may be able to pick some info from these articles :
They are how the author of the Shorewall firewall package configured his systems (two different ways) with similar requirements.

Simon Hobson

Visit http://www.magpiesnestpublishing.co.uk/ for books by acclaimed
author Gladys Hobson. Novels - poetry - short stories - ideal as
Christmas stocking fillers. Some available as e-books.

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