The error "Login failed for user 'NT AUTHORITY\IUSR'" in ASP.NET and SQL Server 2008
asp.net, database-permissions, iis-7, sql-server
Solution
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... ;-)
Problem
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.SqlClient.SqlException: Cannot open database "MyDbName" requested by the login. The login failed. Login failed for user 'NT AUTHORITY\IUSR'. The thing is, I've added `NT AUTHORITY\IUSR` to the server's list of logins, and to the database's list of users. For the server, I've granted the user the Public role, and for the database I've granted `db_datareader` permissions. I've also granted the same for `NT AUTHORITY\NETWORK SERVICE`, which is the identity that the application pool is running under. The web application is hosted by IIS7, if that makes a difference. The problem repros when the DB and IIS are on the same physical machine as well.