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1. Introduction

1.1 Knowledge Required

Creating a virtual services machine is not all that difficult. However, more than fundamental knowledge is required. And this document is not a primer to how to fully configure a Linux machine.

In order to understand this HOWTO document it is assumed that you are thoroughly familiar with the following:

If you are uncertain of how to proceed with any of the above it is STRONGLY recommended that you use the links provided to familiarize yourself with all packages. I will NOT reply to any mail reguarding any of the above. Please direct any questions to the appropriate author of the HOWTO.

1.2 Purpose

The purpose of virtual services is to allow a single machine to recognize multiple IP addresses without multiple network cards. IP aliasing is a kernel option that allows you to assign each network device more than one IP address. The kernel then multiplexes (swaps between them very fast) in the background and to the user it appears like you have more than one network card.

This multiplexing allows multiple domains (,, etc.) to be hosted by the same machine for the same cost as hosting one domain. Unfortunately, most services (ftp, web, mail) were not designed to handle muliple domains. In order to make them work properly you must modify both configuration files and source code. This document describes how to make these modifications in the setting up of a virtual machine.

A deamon is also required in order to make virtual services function. The source for this daemon (virtuald) is provided later in this document.

1.3 Feedback

This document will expand as packages are updated and source or configuration modifications change. If there are any portions of this document that are unclear please feel free to email me with your suggestions or questions. So that I do not have to go searching through the entire HOWTO please make certain that all comments are as specific as possible and include the section where the uncertainty lies. It is important that all mail be addressed with VIRTSERVICES HOWTO in the subject line. Any other mail will be considered personal and all my friends know that I do not ever read my personal mail so it will probably get discarded with theirs.

Please note that my examples are just that, examples and should not be copied verbatim. You may have to insert your own values. If you are having trouble, send me mail, with all the pertinent configuration files and the error messages you get when installing, and I will look them over and mail my suggestions back.

1.4 Revision History

V1.0 Initial version

V1.1 Fixed error in Virtual Web Section

V1.2 Fixed the date

1.5 Copyright/Distribution

This document is Copyright (c) 1997 by The Computer Resource Center Inc.

A verbatim copy may be reproduced or distributed in any medium physical or electronic without permission of the author. Translations are similiarly permitted without express permission if it includes a notice on who translated it. Commercial redistribution is allowed and encouraged; however please notify Computer Resource Center of any such distributions.

Excerpts from the document may be used without prior consent provided that the derivative work contains the verbatim copy or a pointer to a verbatim copy.

Permission is granted to make and distribute verbatim copies of this document provided the copyright notice and this permission notice are preserved on all copies.

In short, we wish to promote dissemination of this information through as many channels as possible. However, I do wish to retain copyright on this HOWTO document, and would like to be notified of any plans to redistribute this HOWTO.

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