trusted connection

Hi,
How is it possible to use trusted connection for an Intranet site?
Intranet is using a webservice which is hosted on a web server on LAN.

This is the connectionstring that I am currently using for the intranet website in the company LAN.
<value>Data Source=SQLMachineName1\MSQL_DEV;Initial Catalog=DBdatabaseName;Persist Security Info=True;User Id=WebUserAccountName;Password=password;</value>


I would like to use this connectionstring instead so that I can have more control over the logged in users.
If I do use this connectionstring the error it gives is:
Login failed for user (null). Not associated with a trusted sql server connection.
<value>Data Source=SQLMachineName1\MSQL_DEV;Initial Catalog=DBdatabaseName;Integrated Security=True</value>

I think the site the user is accessing must be listed in the user's "trusted sites" in IE. Also, in the avanced browser settings for IE, "Use integrated security" has to be checked.

As for the site itself, it needs to be configured to use integrated authentication in IIS.

In the web.config for the site, you need to have the following:

<authentication mode="Windows"/>
<identity impersonate="true"/>

Hope that helps for you.