Alternate access mapping and Server name mapping

Alternate Access Mapping (AAM) and Server Name Mapping are two features SharePoint provides to alter the URLs returned in search results - a common practice used by many companies for their internal and external users. Both features are available in both the out of the box search in SharePoint 2010 and in the new FAST Search Server for SharePoint 2010.

This post is intended for people with working knowledge about the two features who want to know when to use which. If you need to brush up on your basic understanding about the two features, here are a couple good sources for your convenience:

Internet URL auto redirects to Intranet URL

Issue:
Company’s internet site auto redirects to Company’s Intranet site
Scenario:
Company’s intranet Site:              http://abc
Company’s internet Site:              http://abc.xyz.com
One user had added Link Web Part on site and in that link web part when he clicks on http://abc.xyz.com  it auto converts into http://abc  in the web part and internet user is not able to access the site. If he manually changes the URL from http://abc to http://abc.xyz.com then it’s working fine.
Resolution:
I did very basic troubleshooting and the issue got resolved.

• First I went to Central Administration > Operations > AAM settings and checked zone settings for the affected sites. It was looking good.
• Then I went to IIS manager and found that our developer had put redirection URL under Home Directory of that site.
• It was obviously for testing purpose but after testing he did not remove it.
• So I just changed the option to “A directory located on this computer” option and it was working fine as expected.

Feel free to reach me if you have any doubts.