SmtpClient.UseDefaultCredentials Property

Definition

Namespace:

System.Net.Mail

Assembly:

System.Net.Mail.dll

Source:

SmtpClient.cs

Gets or sets a Boolean value that controls whether the DefaultCredentials are sent with requests.

public:
 property bool UseDefaultCredentials { bool get(); void set(bool value); };

public bool UseDefaultCredentials { get; set; }

member this.UseDefaultCredentials : bool with get, set

Public Property UseDefaultCredentials As Boolean

Property Value

Boolean

true if the default credentials are used; otherwise false. The default value is false.

Exceptions

InvalidOperationException

You cannot change the value of this property when an email is being sent.

Examples

The following code example demonstrates using this property.

static void CreateTestMessage2( String^ server )
{
   String^ to = L"jane@contoso.com";
   String^ from = L"ben@contoso.com";
   MailMessage^ message = gcnew MailMessage( from,to );
   message->Subject = L"Using the new SMTP client.";
   message->Body = L"Using this new feature, you can send an email message from an application very easily.";
   SmtpClient^ client = gcnew SmtpClient( server );
   
   // Credentials are necessary if the server requires the client 
   // to authenticate before it will send email on the client's behalf.
   client->UseDefaultCredentials = true;
   client->Send( message );
   client->~SmtpClient();
}

public static void CreateTestMessage2(string server)
{
    string to = "jane@contoso.com";
    string from = "ben@contoso.com";
    MailMessage message = new MailMessage(from, to);
    message.Subject = "Using the new SMTP client.";
    message.Body = @"Using this new feature, you can send an email message from an application very easily.";
    SmtpClient client = new SmtpClient(server);
    // Credentials are necessary if the server requires the client
    // to authenticate before it will send email on the client's behalf.
    client.UseDefaultCredentials = true;

    try
    {
        client.Send(message);
    }
    catch (Exception ex)
    {
        Console.WriteLine("Exception caught in CreateTestMessage2(): {0}",
            ex.ToString());
    }
}

Remarks

Some SMTP servers require that the client be authenticated before the server sends email on its behalf. Set this property to true when this SmtpClient object should, if requested by the server, authenticate using the default credentials of the currently logged on user. For client applications, this is the desired behavior in most scenarios.

Credentials information can also be specified using the application and machine configuration files. For more information, see <mailSettings> Element (Network Settings).

If the UseDefaultCredentials property is set to false, then the value set in the Credentials property will be used for the credentials when connecting to the server. If the UseDefaultCredentials property is set to false and the Credentials property has not been set, then mail is sent to the server anonymously.

Caution

If you provide credentials for basic authentication, they are sent to the server in clear text. This can present a security issue because your credentials can be seen, and then used by others.