Index: /home/maurer/stuff/workspace/james-dev/src/java/org/apache/james/smtpserver/MailCmdHandler.java
===================================================================
--- /home/maurer/stuff/workspace/james-dev/src/java/org/apache/james/smtpserver/MailCmdHandler.java	(revision 394548)
+++ /home/maurer/stuff/workspace/james-dev/src/java/org/apache/james/smtpserver/MailCmdHandler.java	(working copy)
@@ -28,6 +28,7 @@
 import org.apache.james.util.mail.dsn.DSNStatus;
 import org.apache.mailet.MailAddress;
 
+import java.net.UnknownHostException;
 import java.util.Collection;
 import java.util.Locale;
 import java.util.StringTokenizer;
@@ -209,7 +210,16 @@
                 
                     records = dnsServer.findMXRecords(senderAddress.getHost());
                     if (records == null || records.size() == 0) {
-                        badSenderDomain = true;
+                        
+                        try
+                        {
+                            org.apache.james.dnsserver.DNSServer.getByName(senderAddress.getHost());
+                        }
+                        catch (UnknownHostException e)
+                        {
+                            badSenderDomain = true;
+                        }
+
                     }
                 
                     // try to resolv the provided domain in the senderaddress. If it can not resolved do not accept it.
Index: /home/maurer/stuff/workspace/james-dev/src/conf/james-config.xml
===================================================================
--- /home/maurer/stuff/workspace/james-dev/src/conf/james-config.xml	(revision 394291)
+++ /home/maurer/stuff/workspace/james-dev/src/conf/james-config.xml	(working copy)
@@ -727,7 +727,7 @@
             <handler command="EXPN" class="org.apache.james.smtpserver.ExpnCmdHandler"></handler>
             <handler command="MAIL" class="org.apache.james.smtpserver.MailCmdHandler">
                 <!-- If is set to true mail is only accepted if the sender contains -->
-                <!-- a resolvable domain having a valid MX Record associated! -->
+                <!-- a resolvable domain having a valid MX Record or A Record associated! -->
                 <!--
                 <checkValidSenderDomain> false </checkValidSenderDomain>
                 -->