You have a SharePoint Server 2010 server farm that contains one Web server. The Web server has
only one IP address.
You plan to implement the following separate Web applications:
http://portal.contoso.com
http://intranet.contoso.com
http://www.contoso.com

You need to recommend a solution to ensure that users can access all three Web applications.
What should you include in the solution?

A.
host headers

B.
handler mappings

C.
extended zones

D.
alternate access mappings

Explanation:
When you extend a SharePoint web application, you are telling SharePoint to go to IIS and create a
new site, but SharePoint will use it to show the same content. You would normally do that to
support different security, authentication and URLs between an Internet site, Intranet and Extranet,
for example. When you add a host header it is equivalent to going to IIS and modifying the HTTP
bindings for a site, and adding another URL or port.
Generally, for simplicity, it is best to let SharePoint manage IIS and not go changing things in IIS
Manager if you can avoid it.
Host Header site collections are a mechanism to allow you to map different host headers to
individual site collections within the same SharePoint web application.
The purpose of alternate access mappings is to deal with the situation where you have a load
balancer or a proxy server that translates from an external URL to your server’s internal URL. This
ensures that the relative URLs generated by SharePoint when rendering pages are consistent with
the external URL. Configuring alternate access mappings does not automatically add host header
entries.