//---------------------------------------------------------------------------
      // MAIL command request handling.
      //---------------------------------------------------------------------------

      else if(command(input) == "MAIL") {

         sender = cleanEMail(input.substr(5));

         //-------------------------------------------------------------
         // Verify that the senders domain name resolves to an address
         // with an MX record. If not and there is a bounce then we 
         // will not be able to return the bounce message so it is
         // probably a spammer anyway.
         //-------------------------------------------------------------

         if(verifyDomainMX(domainOnly(sender))) {

            cout << "250 OK" << CRLF;
            log.message("Response: 250 OK.");
            recipientList = "";
            state = "MAIL";
         }


      }