Why would you do this?

Users of your website want a friendly name (such as intranet) rather than UKWebSrv01

1.       Go to Start -> Administrator Tools -> Internet Information Services Manager

2.       Expand Web Sites and right click the Web site you want to add the host header to.

3.       Select Properties of the Web site

4.       On the Website tab, click Advanced

5.       In the multiple Identities for this Website section, click Add and complete the following fields:

a.       IP Address                                        Leave as All Assigned

b.      TCP port                                             Type 80

c.       Host Header Value                        Type the name that users will type when accessing the website (e.g. Intranet.mydomain.com)

d.      Click Ok, then click Ok again, and click Ok again to leave the Properties Page

All that remains now is for the domain administrator for DNS to add the new host header name to DNS for the mydomain.com domain and the correct IP Address for the Web server.  Once the DNS entry has replicated, any requests for that URL will be redirected by IIS to the correct website.