Alternate access Mapping and Extended Web application .

Today I decided to explain one of the most tricky concept in SharePoint the Alternate Access Mapping (AAM) .

Before starting lets first discuss the concept of extended web application .
When we extend a web application an IIS website gets automatically created .
Hence an extended application have 1 backend Sql database and 2 front end IIS website .
The two IIS website may have different authentication mechanism .
Eg : 1 person having different indentity (IIS website) and also having different names (URLs).


AAM  is like 1 person having 1 identity (no extra IIS website get created) but having different names (URLs).
There are 2 types of URL we can configured in AAM - Internal and public URL.
Each web application can have maximum of 5 public URL (based on 5 zones Default, Extranet, Intranet, Internet and Custom)and can have unlimited  internal URLs .
Each Zone can have different authentication mechanism

Microsoft recommend the extension of a web application instead of creating the Urls in each zone under one IIS website .

Below are two useful link in this concept :

http://www.youtube.com/watch?v=3s_uY983LXM

http://blogs.msdn.com/b/sharepoint_strategery/archive/2013/05/25/alternate-access-mappings-explained.aspx