/// <summary>
/// Communicate with SMTP server
/// </summary>
/// <param name="domain"></param>
/// <param name="from"></param>
/// <param name="recipient"></param>
/// <returns></returns>
private Result WillAccept(string domain, string from, string recipient)
{
if (Email.ServerName == string.Empty)
{
throw new NullReferenceException("No Email.ServerName has been specified");
}
System.Net.Sockets.TcpClient client =
new System.Net.Sockets.TcpClient(domain, (int)Port.Smtp);
_stream = client.GetStream();
_reader = new System.IO.StreamReader(client.GetStream());
Result status = Result.Succeeded;
string mailServer = Email.ServerName;
string crlf = Environment.NewLine;
if (mailServer == null)
{
mailServer = MxRecord.Infer(from).HostName;
}
// some servers acknowledge connection
if (_reader.Peek() != -1)
{
this.ValidResponse(Response.ConnectSuccess);
}
// HELO
if (!this.SmtpCommand(string.Format("HELO {0}{1}", mailServer, crlf)))
{
status = Result.NoServerGreeting;
}
// MAIL FROM
if (status.Contains(Result.Succeeded) &&
!this.SmtpCommand(string.Format("MAIL FROM:<{0}>{1}", from, crlf)))
{
status = Result.RefusedMailFrom;
}
// RCPT TO
if (status.Contains(Result.Succeeded) &&
!this.SmtpCommand(string.Format("RCPT TO:<{0}>{1}", recipient, crlf)))
{
status = Result.AddressNotFound;
}
// RCPT TO random
// if random address is successful then server is not really validating
if (status.Contains(Result.Succeeded) &&
this.SmtpCommand(string.Format("RCPT TO:<{0}@{1}>{2}", _random,
this.HostPart(recipient), crlf)))
{
status = Result.ValidatedBadAddress;
}
// QUIT
this.SmtpCommand(string.Format("QUIT{0}", crlf), Response.QuitSuccess);
_stream.Close();
_reader.Close();
client.Close();
return(status);
}
/// <summary>
/// Validate an e-mail address by checking the mail server
/// </summary>
/// <param name="from"></param>
/// <param name="recipient"></param>
/// <returns></returns>
public Stack <string> Ping(string from, string recipient)
{
if (!Regex.IsMatch(recipient, _pattern))
{
_stack.Push(Result.BadAddressFormat.ToString());
return(_stack);
}
if (_port25blocked)
{
// execute through web service
/*com.vasst.SMTP smtp = new com.vasst.SMTP();
* //Dim smtp As New com.webott.Utility
* object[] response = smtp.Ping(recipient);
* _stack.Clear();
* for (int x = response.Length - 1; x >= 0; x += -1) {
* _stack.Push(response(x));
* }
*/
}
else
{
// execute locally
Result status = Result.Failed;
string domain = this.HostPart(recipient);
if (_testDomain)
{
try {
IPHostEntry host = System.Net.Dns.GetHostEntry(domain);
} catch {
_stack.Push(Result.DomainNotResolved.ToString());
return(_stack);
}
}
List <MxRecord> mxRecords = DNS.MxQuery(domain);
if (mxRecords.Count == 0)
{
// if no records found then try common mail server name
status = Result.NoMxRecords;
mxRecords.Add(MxRecord.Infer(domain));
}
else
{
mxRecords.Sort();
}
for (int x = 0; x <= mxRecords.Count - 1; x++)
{
status = this.WillAccept(mxRecords[x].HostName, from, recipient);
if (status.Contains(Result.MxComplete))
{
break;
}
}
_stack.Push(status.ToString());
}
return(_stack);
}