Send mail via SMTP Direct

using System;
 using System.Text;
 using System.IO;
 using System.Net.Sockets;
 using System.Net;
 using System.Web.Mail;
 namespace SMTP
 {
 /// 

 /// provides methods to send email via smtp direct to mail server
 /// 
 public class SmtpDirect
 {
 /// 

 /// Get / Set the name of the SMTP mail server
 /// 
 public static string SmtpServer;
 private enum SMTPResponse: int
 {
 CONNECT_SUCCESS = 220,
 GENERIC_SUCCESS = 250,
 DATA_SUCCESS = 354,
 QUIT_SUCCESS = 221 
 }
 public static bool Send(MailMessage message)
 {
 IPHostEntry IPhst = Dns.Resolve(SmtpServer);
 IPEndPoint endPt = new IPEndPoint(IPhst.AddressList[0], 25);
 Socket s= new Socket(endPt.AddressFamily, SocketType.Stream,ProtocolType.Tcp);
 s.Connect(endPt);

 if(!Check_Response(s, SMTPResponse.CONNECT_SUCCESS))
 { 
 s.Close();
 return false;
 }

 Senddata(s, string.Format("HELO {0}\r\n", Dns.GetHostName() ));
 if(!Check_Response(s, SMTPResponse.GENERIC_SUCCESS))
 {
 s.Close();
 return false;
 }

 Senddata(s, string.Format("MAIL From: {0}\r\n", message.From ));
 if(!Check_Response(s, SMTPResponse.GENERIC_SUCCESS))
 {

 s.Close();
 return false;
 }

 string _To = message.To;
 string[] Tos= _To.Split(new char[] {';'});
 foreach (string To in Tos)
 {
 Senddata(s, string.Format("RCPT TO: {0}\r\n", To));
 if(!Check_Response(s, SMTPResponse.GENERIC_SUCCESS))
 { 
 s.Close();
 return false;
 }
 }

 if(message.Cc!=null)
 {
 Tos= message.Cc.Split(new char[] {';'});
 foreach (string To in Tos)
 {
 Senddata(s, string.Format("RCPT TO: {0}\r\n", To));
 if(!Check_Response(s, SMTPResponse.GENERIC_SUCCESS))
 { 
 s.Close();
 return false;
 }
 }
 }

 StringBuilder Header=new StringBuilder();
 Header.Append("From: " + message.From + "\r\n");
 Tos= message.To.Split(new char[] {';'});
 Header.Append("To: ");
 for( int i=0; i< Tos.Length; i++)
 {
 Header.Append( i > 0 ? "," : "" );
 Header.Append(Tos[i]);
 }
 Header.Append("\r\n");
 if(message.Cc!=null)
 {
 Tos= message.Cc.Split(new char[] {';'});
 Header.Append("Cc: ");
 for( int i=0; i< Tos.Length; i++)
 {
 Header.Append( i > 0 ? "," : "" );
 Header.Append(Tos[i]);
 }
 Header.Append("\r\n");
 }
 Header.Append( "Date: " );
 Header.Append(DateTime.Now.ToString("ddd, d M y H:m:s z" ));
 Header.Append("\r\n");
 Header.Append("Subject: " + message.Subject+ "\r\n");
 Header.Append( "X-Mailer: SMTPDirect v1\r\n" );
 string MsgBody = message.Body;
 if(!MsgBody.EndsWith("\r\n"))
 MsgBody+="\r\n";
 if(message.Attachments.Count>0)
 {
 Header.Append( "MIME-Version: 1.0\r\n" );
 Header.Append( "Content-Type: multipart/mixed; boundary=unique-boundary-1\r\n" );
 Header.Append("\r\n");
 Header.Append( "This is a multi-part message in MIME format.\r\n" );
 StringBuilder sb = new StringBuilder();
 sb.Append("--unique-boundary-1\r\n");
 sb.Append("Content-Type: text/plain\r\n");
 sb.Append("Content-Transfer-Encoding: 7Bit\r\n");
 sb.Append("\r\n");
 sb.Append(MsgBody + "\r\n");
 sb.Append("\r\n");

 foreach(object o in message.Attachments)
 {
 MailAttachment a = o as MailAttachment;
 byte[] binaryData;
 if(a!=null)
 {
 FileInfo f = new FileInfo(a.Filename);
 sb.Append("--unique-boundary-1\r\n");
 sb.Append("Content-Type: application/octet-stream; file=" + f.Name + "\r\n");
 sb.Append("Content-Transfer-Encoding: base64\r\n");
 sb.Append("Content-Disposition: attachment; filename=" + f.Name + "\r\n");
 sb.Append("\r\n");
 FileStream fs = f.OpenRead();
 binaryData = new Byte[fs.Length];
 long bytesRead = fs.Read(binaryData, 0, (int)fs.Length);
 fs.Close();
 string base64String = System.Convert.ToBase64String(binaryData, 0,binaryData.Length);

 for(int i=0; i< base64String.Length ; )
 {
 int nextchunk=100;
 if(base64String.Length - (i + nextchunk ) <0)
 nextchunk = base64String.Length -i;
 sb.Append(base64String.Substring(i, nextchunk));
 sb.Append("\r\n");
 i+=nextchunk; 
 }
 sb.Append("\r\n"); 
 }
 }
 MsgBody=sb.ToString();
 }

 Senddata(s, ("DATA\r\n"));
 if(!Check_Response(s, SMTPResponse.DATA_SUCCESS))
 { 
 s.Close();
 return false;
 }
 Header.Append( "\r\n" );
 Header.Append( MsgBody );
 Header.Append( ".\r\n" );
 Header.Append( "\r\n" );
 Header.Append( "\r\n" );
 Senddata(s, Header.ToString());
 if(!Check_Response(s, SMTPResponse.GENERIC_SUCCESS ))
 { 
 s.Close();
 return false;
 } 

 Senddata(s, "QUIT\r\n");
 Check_Response(s, SMTPResponse.QUIT_SUCCESS );
 s.Close(); 
 return true;
 }
 private static void Senddata(Socket s, string msg)
 { 
 byte[] _msg = Encoding.ASCII.GetBytes(msg);
 s.Send(_msg , 0, _msg .Length, SocketFlags.None);
 }
 private static bool Check_Response(Socket s, SMTPResponse response_expected )
 {
 string sResponse;
 int response;
 byte[] bytes = new byte[1024];
 while (s.Available==0)
 {
 System.Threading.Thread.Sleep(100);
 }

 s.Receive(bytes, 0, s.Available, SocketFlags.None);
 sResponse = Encoding.ASCII.GetString(bytes);
 response = Convert.ToInt32(sResponse.Substring(0,3));
 if(response != (int)response_expected)
 return false;
 return true;
 }
 }
 }