Sharepoint Web Application Zones

    Zones provide different logical paths (URL's) to access the same web application. Multiple zone usage allows implementing different access and policy conditions for users. Zones provide a way of using different authentication methods for the same site. In Sharepoint, each web application has 5 zones:

• Default
• Intranet
• Internet
• Custom
• Extranet                                                                                                                                                                   

Zones provide a method to partition users by: 

• Authentication type (Windows Authentication/Kerberos)
• Network zone (Intranet/Internet/Extranet)
• Policy permissions (Allow or Deny Read-Write access)