Connection question about using impersonate in webpage

Hi,
I create a webservice and impersonate a specific user only when you run a
connection to sql server to insert the data.
My connection string is as follows:
Integrated Security=SSPI;Persist Security Info=false;Initial
Catalog=cmcMail;Data Source=MASDD1;Network Library=dbmssocn;Packet Size=1024;
I got the error during debugging which is "Error: 18456, Severity: 14,
State: 11" . It means that "Valid login but server access failure"
After running some testings, I have a few questions about the inpersonate
issue:
1. If I user anohter domain user, who has access right to server and
database even to execute the store procedure as same as the specific user.
The data is inserted without problem. Why one can work and another cann't?
2. I tried to user the user is not my database user but can access another
database on the same SQL server.
It didn't raise error, and the data is insert on the table. Why this user
without premission can execute the store procedure.
Thanks
"BMW" wrote:

> Hi,
> I create a webservice and impersonate a specific user only when you run a
> connection to sql server to insert the data.
> My connection string is as follows:
> Integrated Security=SSPI;Persist Security Info=false;Initial
> Catalog=Mail;Data Source=MAS;Network Library=dbmssocn;Packet Size=1024;
> I got the error during debugging which is "Error: 18456, Severity: 14,
> State: 11" . It means that "Valid login but server access failure"
>
> After running some testings, I have a few questions about the inpersonate
> issue:
> 1. If I user anohter domain user, who has access right to server and
> database even to execute the store procedure as same as the specific user.
> The data is inserted without problem. Why one can work and another cann't?
> 2. I tried to user the user is not my database user but can access another
> database on the same SQL server.
> It didn't raise error, and the data is insert on the table. Why this user
> without premission can execute the store procedure.
> Thanks
>