protected EmailServerStatus CheckEmailServer(string host, int port)
{
EmailServerStatus ess = new EmailServerStatus();
if (CanPingHost(host))
{
ess.Online = true;
}
else
{
ess.Online = false;
return(ess);
}
using (TcpClient client = new TcpClient())
{
client.Connect(host, port);
if (client.Connected)
{
ess.Open = true;
using (NetworkStream stream = client.GetStream())
{
if (SendCommand(stream, "EHLO dnscheck.localhost"))
{
if (SendCommand(stream, "MAIL FROM: [email protected]"))
{
if (SendCommand(stream, "RCPT TO: [email protected]"))
{
ess.AllowsRelay = true;
SendCommand(stream, "QUIT");
}
}
}
stream.Close();
}
}
}
return(ess);
}
protected void MXRecordCheck(DnsResourceRecord record, MxRecord mxrecord)
{
bool online = false;
bool acc25 = false;
bool acc465 = false;
bool acc587 = false;
bool allowsRelay = false;
if (InvokeRequired)
{
WriteLineInvoke("Found MX record " + record.ToString(), Color.Gainsboro);
if (mxrecord == null || mxrecord.Exchange == null)
{
Invoke(new Finished(WriteEmptyLine));
return;
}
UpdateStatusInvoke("Attempting to ping host " + mxrecord.Exchange);
if (CanPingHost(mxrecord.Exchange))
{
online = true;
UpdateStatusInvoke("Attempting to acess host on port 25...");
if (CanReachHost(mxrecord.Exchange, 25))
{
acc25 = true;
}
UpdateStatusInvoke("Attempting to acess host on port 465...");
if (CanReachHost(mxrecord.Exchange, 465))
{
acc465 = true;
}
UpdateStatusInvoke("Attempting to acess host on port 587...");
if (CanReachHost(mxrecord.Exchange, 587))
{
acc587 = true;
}
if (acc25)
{
UpdateStatusInvoke("Attempting to communicate using SMTP on port 25...");
EmailServerStatus ess = CheckEmailServer(mxrecord.Exchange, 25);
if (ess.AllowsRelay)
{
allowsRelay = true;
}
}
}
if (!online)
{
WriteLineInvoke("Host appears offline!", Color.OrangeRed);
}
else
{
WriteStringInvoke("Host online! ", Color.YellowGreen);
WriteStringInvoke("25 ", Color.Gainsboro);
if (acc25)
{
WriteStringInvoke("Open ", Color.YellowGreen);
}
else
{
WriteStringInvoke("Closed ", Color.OrangeRed);
}
WriteStringInvoke("465 ", Color.Gainsboro);
if (acc465)
{
WriteStringInvoke("Open ", Color.YellowGreen);
}
else
{
WriteStringInvoke("Closed ", Color.OrangeRed);
}
WriteStringInvoke("587 ", Color.Gainsboro);
if (acc587)
{
WriteLineInvoke("Open", Color.YellowGreen);
}
else
{
WriteLineInvoke("Closed", Color.OrangeRed);
}
if (allowsRelay)
{
WriteLineInvoke("Warning: Host allows relaying!", Color.OrangeRed);
}
}
Invoke(new Finished(WriteEmptyLine));
}
}
