diff --git a/CHANGELOG b/CHANGELOG
index 45ed3bfd..909a3ed0 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -49,6 +49,10 @@ HISTORY
 
  ++ Bugfixes:
 
+  2011-11-22: Simon Goldschmidt
+  * netif.c, etharp.h/.c: fixed bug #34684: Clear the arp table cache when
+    netif is brought down
+
   2011-10-28: Simon Goldschmidt
   * tcp_in.c: fixed bug #34638: Dead code in tcp_receive - pcb->dupacks
 
diff --git a/src/core/netif.c b/src/core/netif.c
index 342aa87d..07908cc5 100644
--- a/src/core/netif.c
+++ b/src/core/netif.c
@@ -497,6 +497,11 @@ void netif_set_down(struct netif *netif)
     snmp_get_sysuptime(&netif->ts);
 #endif
 
+#if LWIP_ARP
+    if (netif->flags & NETIF_FLAG_ETHARP) {
+      etharp_cleanup_netif(netif);
+    }
+#endif /* LWIP_ARP */
     NETIF_STATUS_CALLBACK(netif);
   }
 }
diff --git a/src/include/netif/etharp.h b/src/include/netif/etharp.h
index 691575fa..859608df 100644
--- a/src/include/netif/etharp.h
+++ b/src/include/netif/etharp.h
@@ -190,6 +190,7 @@ err_t etharp_request(struct netif *netif, ip_addr_t *ipaddr);
  *  nodes to update an entry in their ARP cache.
  *  From RFC 3220 "IP Mobility Support for IPv4" section 4.6. */
 #define etharp_gratuitous(netif) etharp_request((netif), &(netif)->ip_addr)
+void etharp_cleanup_netif(struct netif *netif);
 
 #if ETHARP_SUPPORT_STATIC_ENTRIES
 err_t etharp_add_static_entry(ip_addr_t *ipaddr, struct eth_addr *ethaddr);
diff --git a/src/netif/etharp.c b/src/netif/etharp.c
index b63d577b..286f7fe3 100644
--- a/src/netif/etharp.c
+++ b/src/netif/etharp.c
@@ -106,9 +106,7 @@ struct etharp_entry {
   struct pbuf *q;
 #endif /* ARP_QUEUEING */
   ip_addr_t ipaddr;
-#if LWIP_SNMP
   struct netif *netif;
-#endif /* LWIP_SNMP */
   struct eth_addr ethaddr;
   u8_t state;
   u8_t ctime;
@@ -574,6 +572,23 @@ etharp_remove_static_entry(ip_addr_t *ipaddr)
 }
 #endif /* ETHARP_SUPPORT_STATIC_ENTRIES */
 
+/**
+ * Remove all ARP table entries of the specified netif.
+ *
+ * @param netif points to a network interface
+ */
+void etharp_cleanup_netif(struct netif *netif)
+{
+  u8_t i;
+
+  for (i = 0; i < ARP_TABLE_SIZE; ++i) {
+    u8_t state = arp_table[i].state;
+    if ((state != ETHARP_STATE_EMPTY) && (arp_table[i].netif == netif)) {
+      etharp_free_entry(i);
+    }
+  }
+}
+
 /**
  * Finds (stable) ethernet/IP address pair from ARP table
  * using interface and IP address index.