IIS Web Sites are merely reference pointers for SharePoint Web Applications. These reference pointers contain information as well, so it might be better to think of them as an object that inherits the sharepoint web application. You can have an extranet application with FBA and an Intranet with AD authentication go to the same content in sharepoint.
BEST PRACTICE: A lot of the time I see organizations that wait weeks to create their default web application because they are waiting on a A record in DNS to be created. This is ridiculous. You don’t have to wait, and in fact it is bad practice to create web applications with host headers in them. The default web application should be created with a port number off of the Server Name. This way your sharepoint environment is not dependent of DNS naming. And say someone wants to change the name of their sharepoint site. This concept makes that easiar to handle.
Before we get into the steps involved in this best practice scenario. Lets look into what makes an IIS web application unique from one another and also how IIS directs traffic and composes a sharepoint site.
First off, the uniqueness of an IIS web site is determined by three things: Server Name/IP Address, Host Header and port number. Since your servername is already registered on your network for its IP Address, the server name can be used for sharepoint web application out of the box. When you do an A Record DNS Mapping to your servers IP address, or a B Record to your server name… When a request is routed by DNS, it is appended with the host header information as well as the IP address and port number. This is a point that some IT Personnel do not understand, IIS goes down the list of IIS Websites until it maps not only the IP address and port number, but also the host header. So you can have multiple port 80 web sites on the same IIS Server.
Tags: Authentication, IIS, IIS and SharePoint, MOSS, SharePoint
chadclarke