diff --git a/CHANGELOG b/CHANGELOG
index 1ba0154c..0ea3660b 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -131,6 +131,10 @@ HISTORY
 
   ++ Bugfixes:
 
+  2010-02-14: Simon Goldschmidt
+  * opt.h: Disable ETHARP_TRUST_IP_MAC by default since it slows down packet
+    reception and is not really necessary
+
   2010-02-14: Simon Goldschmidt
   * etharp.c/.h: Fixed ARP input processing: only add a new entry if a
     request was directed as us (RFC 826, Packet Reception), otherwise
diff --git a/src/include/lwip/opt.h b/src/include/lwip/opt.h
index c7e92c35..ab5be05a 100644
--- a/src/include/lwip/opt.h
+++ b/src/include/lwip/opt.h
@@ -411,9 +411,11 @@
  * correct addresses, or as a limited approach to attempt to handle
  * spoofing. If disabled, lwIP will need to make a new ARP request if
  * the peer is not already in the ARP table, adding a little latency.
+ * The peer *is* in the ARP table if it requested our address before.
+ * Also notice that this slows down input processing of every IP packet!
  */
 #ifndef ETHARP_TRUST_IP_MAC
-#define ETHARP_TRUST_IP_MAC             1
+#define ETHARP_TRUST_IP_MAC             0
 #endif
 
 /**