Database + Windows Authentication + Username/Password?

Question

I have always thought that in order to connect to SQL server using windows authentication with explicitly specified credentials, you must LogonUser, Impersonate, then connect.

It seems to me that this link suggests that it's possible to connect to SQL server without all this hassle, simply by specifying "uid=...;pwd=..." in connection string. I tested this method just to be sure it doesn't work, and - lo and behold - it didn't. If that blog post wasn't on msdn.com, I would have just dismissed it as noob talk, but it is.

Does anyone have an idea what am I missing?

EDIT1: Many respondents misunderstood what I was referring to. Here's a copy/paste of what I was talking about. It's not integrated SQL, nor it's an ASP.NET impersonation made by IIS:

string sql4 = String.Format(    @"Data Source={0};Integrated Security=SSPI;uid=<uid>;pwd=<pid>", server);      // Database + Windows Authentication + Username/Password 

Answer 1

There are two distinct kinds of security with SQL Server. "Windows Authentication", and "SQL Server Authentication". When you see uid and pwd you're seeing the latter. The uid in this case is not a Windows principal - the OS knows nothing about it.

So the answer to your question is, no, you can't pass Windows user name and password in the connection string to log in to SQL Server.