Windows Knowledge Base

[Server Tutor] How to Hosting Multiple Sites on One Physical Machine

Hosting multiple Web sites can be done in three ways.The most common is to assign an IP address to
every new Web site.This used to be the most common practice.The obvious limitation is the number
of IP addresses available for the organization.IIS 6 provides three different methods by which you can host multiple virtual web sites on one set of physical hardware: The following is the IIS 6.0 process to assign an IP address for a particular site:
1. Open IIS Manager.
2. Select the server and right-click on the Web site.
3. Click Properties and select the Web Site tab.
4. Click the IP address combo box and select or type the IP address your Web site should
refer to. Click the OK button at the bottom

Picture-1  Assign IP address

The second option is Much like the multiple IP addresses method, all virtual sites share a single hard-wired IP address on a physical machine, but the individual sites are listening on different TCP port numbers. This is a bit clunky on the users' side because they often need to remember a specific port number when surfing to a site that's configured like this, but for intranet use, it's a good way to conserve hardware. Some might argue that it is also a decent security improvement because the hackers have to search for the web service to crack it, instead of simply assuming it's on the standard port 80. Hackers commonly use port scanners, though, so you succeed only in keeping out the people interested in the easiest targets. You also can implement redirection solutions so that public-facing users don't have to enter a port number, although those programs and boxes are beyond the scope of this discussion.

Picuture-2  TCP Port Number direct traffic to the appropriate site when a single IP is used for multiple sites.

The last option is to assign unique host headers on a single IP address.The host

headers are unique DNS names that identify different Web sites. IIS will channel all the
requests for a single IP address and filter them using the header information.The filter process
will forward them to the correct Web site according to the header name.This is a
good mechanism to implement small to medium Web sites on a single machine.We need
dedicated IP addresses for large Web sites.

Picuture-3 Host headers direct traffic to the appropriate site when a single IP is used for multiple sites.

Here is the process to create a header for a site. Follow the steps from 1 to 4 from the last example.
Then click the Advance button.You will get the following window

Picture-4  Add Host Header