diff --git a/docs/MultiISP.xml b/docs/MultiISP.xml
index 8c4effa87..b1d24c7de 100644
--- a/docs/MultiISP.xml
+++ b/docs/MultiISP.xml
@@ -15,7 +15,7 @@
       </author>
     </authorgroup>
 
-    <pubdate>2006-05-07</pubdate>
+    <pubdate>2006-05-20</pubdate>
 
     <copyright>
       <year>2005</year>
@@ -560,6 +560,10 @@ net        net            DROP</programlisting>
 eth0             130.252.99.27     206.124.146.176
 eth1             206.124.146.176   130.252.99.27</programlisting>
 
+      <para>Those entries ensure that traffic originating on the firewall
+      always has the source IP address corresponding to the interface that it
+      is routed out of.</para>
+
       <note>
         <para>If you have a Dynamic IP address on either of the interfaces,
         you can use shell variables to construct the above rules. For example,