You experience search related errors after you enable "Use a dedicated web front end computer for crawling" setting in Office SharePoint Server 2007

 

Consider the following scenario:

• You install Microsoft Office SharePoint Server 2007 on Windows Server 2008 or Windows Server 2008 R2.
• You configure an IPv6 address for the Windows Server.
• You enable "Use a dedicated web front end computer for crawling" setting in Office SharePoint Server 2007.

In this scenario, you experience search related errors. For example, you may experience any of the following errors:

• Crawl cannot start.
• Search setting page errors occur.
• Central Admin cannot be opened on the indexer server.

https://support.microsoft.com/kb/981452