I don't think you would be able to enumerate them under all circumstances because SQL 2005 and later installation by default disables SQL Server Browser service which makes enumeration possible.

>I know there was a thread on this 5 years ago but I the solutions presented there are not quite working for me.
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>I need a means to enumerate and list all the SQL Server accessible to a machine. The solution I saw uses NetServerEnum() which I guess worked fine for SQL Server 2000 but it doesn't properly return names of servers + instances as used by SQL Server 2005.
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>Any ideas?
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>PS, I would prefer not to rely on any SQL Server functionality existing on the machine...
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>Thanks in advance