asp.net SQL Server Authentication using Windows Authentication

Question

I am currently working on a ASP.NET admin dashboard. The app pool for this IIS website is running with a domain user, which is used to connect to a SQL Server that holds various data for the webpage.

Now, on this website I want to connect to many different SQL Servers using either SQL Server Authentication (if the SQL Server is in a different domain) or Windows Authentication (a separate Windows Account for each SQL Server).

In SQL Server Reporting Services we can create data sources and define how to connect to the databases - basically I want to do the same, but within my ASP.NET code. The authentication information will be stored in a SQL Table (encrypted) accessed by the app pool user.

And no - I can't use SQL Server Reporting Services =)

Additionally, I need to connect to SQL Servers starting 2005 up to 2017 or any upcoming new version. I will have 5 - 100 Servers that I need to query (depending on the scenario).

How can I do that? Did anybody implement something like this? Do you have any tutorials or references?

Thanks in advance

Answer 1

In order to that, I need to use an UserImpersonation Class provided by the "UserImpersonation" nuget package.

Here is a code snippet with which I've test the three authentication methods:

• App Pool Identity
• SQL Server Authentication

• Windows Authentication with Impersonation

   public string TestLogin(string UserName, string Password, string Auth, string Domain) { string thisLogin = ""; //App Pool Identity if (Auth.Equals("local")) { using (SqlConnection cn = new SqlConnection(ConfigurationManager.ConnectionStrings["sqlConn"].ToString())) { SqlCommand cmd = new SqlCommand("SELECT SUSER_SNAME()", cn); cn.Open(); SqlDataReader rdr = cmd.ExecuteReader(); while (rdr.Read()) { thisLogin = rdr[0].ToString(); } cn.Close(); } } if(Auth.Equals("SQL")) { using (SqlConnection cn = new SqlConnection("Data Source = .\\\\D01; Initial Catalog = master; Integrated Security = false; User ID = " + UserName + "; Password=" + Password + ";")) { SqlCommand cmd = new SqlCommand("SELECT SUSER_SNAME()", cn); cn.Open(); SqlDataReader rdr = cmd.ExecuteReader(); while(rdr.Read()) { thisLogin = rdr[0].ToString(); } cn.Close(); } } if(Auth.Equals("Remote")) { string login = UserName; string domain = Domain; string password = Password; using (UserImpersonation user = new UserImpersonation(login, domain, password)) { if (user.ImpersonateValidUser()) { using (SqlConnection cn = new SqlConnection("Data Source = .\\\\D01; Initial Catalog = master; Integrated Security = SSPI;")) { SqlCommand cmd = new SqlCommand("SELECT SUSER_SNAME()", cn); cn.Open(); SqlDataReader rdr = cmd.ExecuteReader(); while (rdr.Read()) { thisLogin = rdr[0].ToString(); } cn.Close(); } } } } if(thisLogin.Equals("")) { thisLogin = "User failed"; } return thisLogin; } 

It's not perfect - but it should work.