The updated mail sending class supports SMTP authentication. Currently, no attachment adding function, CC, or Bcc are available. -E-mail topic -.

This is mainly for your own use. You can expand it on your own.
All code:
Using System;
Using System. Text;
Using System. IO;
Using System. Net;
Using System. Net. Sockets;
Namespace OSLeagueForumXP. Components
{
/// <Summary>
/// TcpClient derived class for SMTP server connection
/// </Summary>
Public class SMTPClient: TcpClient
{
/// <Summary>
/// Connect to the SMTP server
/// </Summary>
Public SMTPClient ()
{
}
/// <Summary>
/// Whether to connect
/// </Summary>
/// <Returns> the connection is True, and the connection is False if no connection is established. </returns>
Public bool isConnected ()
{
Return Active;
}

/// <Summary>