diff --git a/MailServer/MailServer/Configuration.cs b/MailServer/MailServer/Configuration.cs
index d3db0d5..fb90f2d 100644
--- a/MailServer/MailServer/Configuration.cs
+++ b/MailServer/MailServer/Configuration.cs
@@ -7,6 +7,7 @@ namespace MailServer
     public class Configuration
     {
         public const string Hostname = "localhost";
-        public bool STARTTLS_Active = false;
+        public const bool STARTTLS_Active = true;
+        public const int MaxMessageSizeInKb = 500000;
     }
 }
diff --git a/MailServer/MailServer/SMTPServer/MTACommands.cs b/MailServer/MailServer/SMTPServer/MTACommands.cs
index 537ace2..9117df3 100644
--- a/MailServer/MailServer/SMTPServer/MTACommands.cs
+++ b/MailServer/MailServer/SMTPServer/MTACommands.cs
@@ -69,6 +69,13 @@ namespace MailServer.SMTPServer
         AUTH_LOGIN
     }
 
+    public enum Extensions
+    {
+        PIPELINING,
+        SIZE,
+        STARTTLS,
+    }
+
     public enum ResponseCodes
     {
         C211 = 211,
diff --git a/MailServer/MailServer/SMTPServer/SmtpServerSession.cs b/MailServer/MailServer/SMTPServer/SmtpServerSession.cs
index 62805ba..b05004e 100644
--- a/MailServer/MailServer/SMTPServer/SmtpServerSession.cs
+++ b/MailServer/MailServer/SMTPServer/SmtpServerSession.cs
@@ -79,7 +79,7 @@ namespace MailServer.SMTPServer
                                         var res3 = context.Accounts.Where(x => x.Domain.Equals(domain) && x.CatchAll == true);
                                         if (res3.Count() < 1)
                                         {
-                                            //ToDo unmöglich machen!!
+                                            accountId = 0;
                                         }
                                         else
                                         {
@@ -145,6 +145,22 @@ namespace MailServer.SMTPServer
                 switch (command.Command.ToUpper())
                 {
                     case "EHLO":
+                        if (command.Parameters.Length < 1)
+                        {
+                            SendResponse(ResponseCodes.C501, "Hostname Required");
+                            return;
+                        }
+                        SenderHostname = command.Parameters[0];
+                        Initialized = true;
+                        SendExtensionResponse(Extensions.PIPELINING);
+
+                        if (Configuration.STARTTLS_Active)
+                        {
+                            SendExtensionResponse(Extensions.STARTTLS);
+                        }
+
+                        SendResponse(ResponseCodes.C250, "SIZE " + (Configuration.MaxMessageSizeInKb * 1000).ToString());
+                        return;
                     case "HELO":
                         if (command.Parameters.Length < 1)
                         {
diff --git a/MailServer/MailServer/SMTPServer/SmtpSession.cs b/MailServer/MailServer/SMTPServer/SmtpSession.cs
index fd4b01a..bf7fcdf 100644
--- a/MailServer/MailServer/SMTPServer/SmtpSession.cs
+++ b/MailServer/MailServer/SMTPServer/SmtpSession.cs
@@ -36,14 +36,18 @@ namespace MailServer.SMTPServer
             Worker.Start();
         }
 
+        public void SendExtensionResponse(Extensions extension) => SendResponse("250-" + extension.ToString());
+
         public void SendResponse(ResponseCodes responseCode) => SendResponse(responseCode, "");
 
-        public void SendResponse(ResponseCodes responseCode, string args)
+        public void SendResponse(ResponseCodes responseCode, string args) => SendResponse(((int)responseCode).ToString() + " " + args);
+       
+
+        public void SendResponse(string response)
         {
-            var text = ((int)responseCode).ToString();
-            Logging.AddLogMessage(Logging.LoggingType.DEBUG, "Send back: " + text + " " + args);
-            text += " " + args +'\r' + '\n';
-            var bytes = Encoding.UTF8.GetBytes(text);
+            Logging.AddLogMessage(Logging.LoggingType.INFO, response);
+            response += '\r' + '\n';
+            var bytes = Encoding.UTF8.GetBytes(response);
             Stream.Write(bytes, 0, bytes.Length);
         }