Exception when deploying to IIS: Login failed for user 'IIS APPPOOL\DefaultAppPool' - wcf

Question

I'm working through some WCF examples in "Windows Communication Foundation 4 Step By Step". My resulting application runs fine as long as the service is hosted in casini. It fails when I deploy the service to local IIS. When deployed to IIS, I can browse to the svc page in IE. That works.
According to the book, page 41, the app pool account needs to be a member of the db_owner role in my database. The author suggests, after verifying the correct address of the service (already did that), checking the permissions of the app pool account.
How do I verify which account is used by the application pool hosting my WCF service? Currently using the default app pool and IIS APPPOOL\DefaultAppPool is in the db_owner role. IIS APPPOOL\ASP.NET v4.0 is also in the db_owner role.
The exception is...
System.Data.SqlClient.SqlException: Login failed for user 'IIS APPPOOL\DefaultAppPool'.
How do I troubleshoot this issue? Thanks!

Answer 1

Solution found here:
Open IIS
double click your PC name under Connections
Click Application Pools
Select your app pool (DefaultAppPool)
Then under actions on the right click Advanced Settings,
Go to Process Model section and
click on Identity.
Now select NetworkService.

Answer 2

I had the same problem. Issue was that I had "IntegratedSecurity=True;" in my connection string but I was using sql authentication and passing in credentials at the same time. I removed the IntegratedSecurity piece and everything worked.

Answer 3

First thing you need to clear if you are using windows authentication and you are not mentioning any username password in your connection string then:
What happens when you run your code through localhost:
when you run your wcf test client from localhost, it will be able to communicate to database as local debug mode application is calling database by your account's service. So it has access to database because devenv.exe is running under your user account.
But when you deploy your web service in IIS. Now understand this service runs under IIS not under your account. So you need to assign access rights to IIS service to access the sql server for windows authentication.
Here your web service would not be able to communicate to the SQL server because of access rights issue.
So if you are using windows authentication to connect your database, you just have to change the IIS Application pool settings.
You need to change IIS Application pool's identity to local System.
Below are the Steps for windows authentication WCF:
•Open IIS (windows+R (run) then type inetmgr, then click ok)
•double click your PC name under Connections
•Click Application Pools
•Select your app pool (DefaultAppPool)
•Then under actions on the right click Advanced Settings:
•Go to Process Model section and
•click on Identity.
•Now select LocalSystem.
Now open your sql server management studio:
open run-> then type ssms then press ok
in ssms, login using your windows authentication account.
open security tab
expand logins tab
then you will be able to view your account.
Now open properties of your account
go to userMapping
then select the database you want to connect
then check the role membership services you want to use for the selected database
click ok.
add Trusted_Connection=True; property in your connection string.
Save it & deploy the web service.
Restart app pool.
you will be able to connect the database now.

Answer 4

if not exists
(select * from sys.server_principals where name='IIS APPPOOL\DefaultAppPool')
create login [IIS APPPOOL\DefaultAppPool] from windows;