How Can I Access Sql Server In Another Pc?

string connetionString = null;

            //string sql = null;
            string name = "";
            string pass = "";

            connetionString = "Data Source=172.21.1.91,1433;Initial Catalog=EnqInfo;Integrated Security=True";


            using (SqlConnection con = new SqlConnection(connetionString))
            {
                //
                // Open the SqlConnection.
                //
                con.Open();
                //
                // The following code uses an SqlCommand based on the SqlConnection.
                //
                using (SqlCommand command = new SqlCommand("SELECT * FROM Login WHERE U_Name=@Usr", con))
                    {

                        command.Parameters.AddWithValue("@Usr", UName.Text);
                        SqlDataReader reader = command.ExecuteReader();
                        while (reader.Read())
                        {
                            name = reader.GetString(1);  // Name string
                            pass = reader.GetString(2); // Password string
                        }

                        if (name == UName.Text && pass == PWord.Text)
                        {

                            ClassEnq.Uname = UName.Text;
                            MessageBox.Show("Password Accepted");
                            this.Close();
                            setEnableToolStripMenuItem(true);
                            setEnableToolStripMenuItem1(true);
                            setDisableToolStripMenuItem(false);

                        }

                        else
                        {
                            MessageBox.Show("Password Incorrect, Please Re-Enter Your Password");
                            setEnableToolStripMenuItem(false);
                            setEnableToolStripMenuItem1(false);
                        }
                    }