Assigned to user or computer accounts in AD, SPNs define what services run under the account’s security context. When SQL Server Service is using a Service Account instead of the default “LocalSystem”, an example SPN delegated to the account would be: MSSQLSvc/sqlsrvr.exampledomain.com:1433. When an IIS Web Application Pool is running as a specified user account rather than as the default of “Network Service”, an example SPN delegated to the account would be: http/websrvr.exampledomain.com.