Virtual Hosting

Virtual hosting means your data center uses two or more IP addresses to distinguish between web servers on the same physical host computer.

A data center could use virtual hosting to give the appearance that two web sites are completely separate, even though they reside on the same physical computer. For example, say Company A and Company B each have their own mainframe and web site. Company A purchases Company B and merges data processing operations onto one physical computer. Using virtual hosting, the computer can serve both web sites while preserving their respective IP addresses and domain names, which are familiar to their existing users. To a web browser user, it appears as though the web sites are on different physical host computers.

Virtual Hosting Models

You can institute virtual hosting at your site using one of several models. These models are presented below.

Model 1: Single VM:Webgateway Machine

In this model there is one VM:Webgateway SVM. The SVM has multiple IP addresses that can, but are not required to, use the same TCP port. There is no practical limit to the number of TCP sockets you may configure in the VM:Webgateway SVM. All TCP sockets in this SVM share a common VM:Webgateway configuration.

Because there is only one configuration, this model is simple to maintain. For example, you need maintain only one set of system administrators and one set of filetypes.

Model 2: Multiple VM:Webgateway Machines

In this model there are multiple VM:Webgateway SVMs, each with its own userid. The SVMs have distinct IP addresses that can, but are not required to, use the same TCP port. The machines are configured independently of one another, so each TCP socket is part of a different VM:Webgateway configuration.

This model provides the advantage of separated security profiles. For example, you could define certain CGI programs to run on one SVM but not another.

This model also provides the security needed when two groups who do not trust each other both want to use VM:Webgateway. Under this model, each group would have its own VM:Webgateway service virtual machine. This might be advantageous if, say, two competing research groups at a university do not want the other to see their work.

Another Possible Configuration—One IP Address with Multiple TCP Ports

Although not a form of virtual hosting, you can also configure your VM:Webgateway SVM to use one IP address and multiple TCP ports. The advantage of this configuration is that you can have one VM:Webgateway SVM with a single domain name serve data from both a secure TCP socket and a non-secure TCP socket.

The figure below illustrates this configuration.