diff --git a/Changes b/Changes
index dbd6d78..147e17e 100644
--- a/Changes
+++ b/Changes
@@ -8,4 +8,9 @@
   support and enable taint checking (thanks to Devin Carraway
   <qpsmtpd@devin.com>)
 
+  Make the MAIL FROM host dns check configurable. (thanks to Devin
+  Carraway).
+
+  Add more documentation to the README file.
+  
 
diff --git a/README b/README
index fe50809..c576b42 100644
--- a/README
+++ b/README
@@ -6,3 +6,36 @@ mailinglist:
   qpsmtpd-subscribe@perl.org
 
 
+Configuration files:
+  All configuration files goes into $DIR/config/ or /var/qmail/control/
+
+  qpsmtpd is supposed to support all the files that qmail-smtpd
+  supports and use them in the same way.  When you find that it is not
+  the case, feel free to send a patch to the mailinglist or to
+  ask@develooper.com.
+
+  Extra files you can use to configure qpsmtpd:
+
+     rhsbl_zones
+ 
+        Right hand side blocking lists, one per line. For example:
+
+           dsn.rfc-ignorant.org does not accept bounces - http://www.rfc-ignorant.org/
+
+        See http://www.rfc-ignorant.org/ for more examples.
+
+
+     dnsbl_zones
+
+        Normal ip based dns blocking lists ("RBLs"). For example:
+
+           relays.ordb.org
+	   spamsources.fabel.dk
+
+
+     require_resolvable_fromhost
+         
+        If this file contains anything but a 0 on the first line,
+        envelope senders will be checked against DNS. If an A or a MX
+        record can't be found the mail command will return a soft
+        rejection (450).
diff --git a/config.sample/require_resolvable_fromhost b/config.sample/require_resolvable_fromhost
new file mode 100644
index 0000000..ce052b5
--- /dev/null
+++ b/config.sample/require_resolvable_fromhost
@@ -0,0 +1,3 @@
+1
+
+# use 0 to disable; anything else to enable.
\ No newline at end of file
diff --git a/qpsmtpd b/qpsmtpd
index 893e4cb..1ce8be5 100755
--- a/qpsmtpd
+++ b/qpsmtpd
@@ -2,8 +2,7 @@
 # Copyright (c) 2001 Ask Bjoern Hansen. See the LICENSE file for details.
 # The "command dispatch" system is taken from colobus - http://trainedmonkey.com/colobus/
 #
-# this is designed to be run under tcpserver
-# (http://cr.yp.to/ucspi-tcp.html)
+# this is designed to be run under tcpserver (http://cr.yp.to/ucspi-tcp.html)
 # or inetd if you're into that sort of thing
 #
 #
@@ -140,6 +139,7 @@ sub mail {
     return respond(501, "could not parse your mail from command") unless $from;
 
     $from->format ne "<>"
+      and get_config("require_resolvable_fromhost")
       and !check_dns($from->host)
       and return respond(450, "Could not resolve ". $from->host);