The error “Login failed for user 'NT AUTHORITY\IUSR'” in ASP.NET and SQL Server 2008

Question

My ASP.NET v3.5 web application is throwing the following exception when it attempts to open a connection to a SQL Server 2008 database:

System.Data.SqlC

Answer 1

The trick here is that NT AUTHORITY\NETWORK SERVICE actually appears to the database as DOMAINNAME\MACHINENAME$ (note the $ sign!). That is, when you cross the machine boundary from your web server to the SQL Server, SQL Server sees the machine account if you use the NETWORK SERVICE or LOCAL SYSTEM accounts. If you use any other non-domain account, SQL Server will not receive your credentials.

I'm a bit puzzled by your error message. Truth be told, I don't think that when the DB is on another box, you'll see anything other than Login Failed for NT AUTHORITY\ANONYMOUS LOGON.

IUSR is used for anonymous websites, and can't pass over the wire to SQL Server. You may find a way for it to work if you're doing everything on the same machine, but I'd never know because I'd never do it that way... ;-)