ecff48ad_ion_using_Domain_User_Accounts__2
[0] Content access account [1] A specific account that is configured to access a content source. This account is optional and is specified when you create a new crawl rule. For example, content sources that are external to Office SharePoint Server (such as a file share) might require a different content access account. [3] - Read access to external or secure content sources that this account is configured to access. - For Web sites that are not a part of the server farm, this account must explicitly be granted Full Read permissions on the Web applications that host the sites. [4] Server farm standard requirements with the following additions or exceptions: - Use a separate domain user account. [5] Server farm standard requirements with the following additions or exceptions: - Use a separate domain user account. - NOT a member of the Administrators group on any server in the farm, including the computer running SQL Server. - NOT a SQL Server login. [6] Server farm standard requirements with the following additions or exceptions: - Use a separate domain user account. [2] 
Same as the SSP default content access account listed previously.
MOSS How to ...: Starting and Configuring Office SharePoint Server Search for a web server with Least Privilege Administration using Domain User Accounts
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