System administrators often deploy Microsoft Office SharePoint Portal Server 2003 portal sites that users can access by using different URLs. It is important that functionality, such as search results for portal site and document library content, be appropriate for the URL that was used to access the portal site. Users normally expect the URL of a Web site or portal site to be logically connected to the site. External URLs must be in a form that is appropriate for how the user is currently accessing the portal site.

Without alternate access settings, search results might be displayed in a way that would make them inaccessible to users. Users might receive search results that they cannot access whenever they access the portal site by using a URL that is different from the original URL used for crawling the content.

Alternate access settings provide a mechanism for server farm administrators to identify the different ways in which users access portal sites, ensuring that URLs are displayed appropriately for the manner in which the user accesses the site.

SharePoint Portal Server uses a service called Microsoft SharePoint PS Search. This service consults the alternate access setting entries when crawling a document. If the URL of the document matches one of the mapping entry URLs, the URL is replaced with the mapping ID for the entry. When the search result is displayed, the mapping ID is replaced by the appropriate URL. This assumes the user is requesting the document from an access point listed in the alternate access setting entries. If there is no appropriate alternate mapping, the search results display the default URL.

Every alternate access setting entry must have a default URL. Each entry can have additional alternate access methods for either intranet, extranet, or custom access. Each URL must be different from all other URLs. These mappings are stored in the configuration database. SharePoint Portal Server uses the default URL for any requested URL that is not found in the mapping table.

If an entry has been deleted, but URLs for that mapping ID still exist in the index, the server farm administrator must update the content index to update the URLs.

For example:

Imagine that the server you are using for your search is http://Server1. The server has an intranet URL of http://Server1 and an extranet URL of http://AdventureWorks.adventure-works.com. This server does not have SharePoint Portal Server installed but could be another internal server in your organization.

You have not defined an alternate access setting entry for this server. When SharePoint Portal Server crawls Server1, the URL stored in the content index is http://Server1.

When a user preforms a search on this server, one of the following actions occurs:

• If a user is accessing the portal site from the intranet URL of http://Server1, that user will get search results returned for content on Server1 and will be able to click the links for the results to access a document.
• If a user is accessing the portal site from the extranet URL of http://AdventureWorks.adventure-works.com, he or she will get search results returned for content on Server1, but the user will get an error when he or she clicks the links for the results.

Suppose you define an alternate access setting entry for http://Server1 as follows:

• Mapping Name: Server1
• Default URL: http://Server1
• Intranet URL: Left blank. A blank entry returns the default URL.
• Extranet URL: http://AdventureWorks.adventure-works.com
• Custom URL: https://AdventureWorksPartners.adventure-works.com

Custom URLs can be intranet or extranet URLs. In addition, you can use Secure Sockets Layer (SSL) in any of the URL entries. In this case, the URL for Custom URL is for a secure site that uses SSL.

For this mapping to take effect, you must recrawl the content on Server1. Until you do this, the user will have the same search experience as above.

After you recrawl the content on Server1 using the new access settings, when a user performs a search, one of the following occurs:

• If the user is accessing the portal site from the intranet URL that is specified in the access settings list, he or she will get search results returned for content on Server1 and will be able to click the links for the results to access a document.
• If the user is accessing the portal site from the extranet URL that is specified in the access settings list (for example, http://AdventureWorks.adventure-works.com), he or she will get search results returned for content on AdventureWorks.adventure-works.com and will be able to click the links for the results to access a document.

If you are using shared services, in which portal site services are shared across server farms, the following applies for alternate access settings:

• You must manually synchronize the alternate access entries for the parent server farm and all child server farms. If you add, change, or delete an alternate access setting entry on the child server farm, you must add, change, or delete that entry on the parent server farm.

The portal site and document library URLs are generated from the alternate access setting list for the child server farm. Search results use URLs from the alternate access setting list for the parent server farm. Changing an entry in the alternate access setting list (such as changing a default URL, or adding or changing an extranet URL) requires you to do this on both the child server farm and parent server farm.

• The alternate access entry list in the parent server farm should be a superset of the alternate access entry lists in all child server farms. Each child server farm must keep alternate access entries for its portal sites and document libraries up-to-date.

Note  If the server farm administrator enters an invalid URL on the Configure Alternate Portal Access Settings page, the My Site and Alert Me links in a child portal site will be broken.