<snip> I have a whole virtual directory off the root web (IIS), and all my applications in that directory are displaying weird connectivity problems with the SQL Server 2005 database they're supposed to talk to. It seems that whenever an application I am hosting in this directory is forced to recompile, such as when I perform an iisreset, recompile the code, what-have-you, when I first run the affected applications, I get a "SQL Server does not exist or access denied" error. And then, after five to fifteen minutes or so, the applications just... start connecting again. </snip> In case anyone else runs into this same problem, this seems to have been an internal DNS issue. I changed the server name passed in to the connection string to an IP Address (something I should have done anyway), and now everything works fine.