Index: doc/manual/en_US/user_Networking.xml
===================================================================
--- doc/manual/en_US/user_Networking.xml	(revision 46693)
+++ doc/manual/en_US/user_Networking.xml	(working copy)
@@ -356,7 +356,10 @@
             ICMP protocol for sending/receiving messages. While ICMP support
             has been improved with VirtualBox 2.1
             (<computeroutput>ping</computeroutput> should now work), some
-            other tools may not work reliably.</para>
+            other tools may not work reliably. Please note: for Windows hosts
+            ICMP isn't implemented in socket API, instead the ICMP API is used,
+            which has its own bottlenecks and cannot be used as diagnostic
+            tool. This affects all guests.</para>
           </glossdef>
         </glossentry>
 
