diff --git a/CHANGELOG b/CHANGELOG
index 34078239..de30305b 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -23,6 +23,10 @@ HISTORY
 
   ++ New features:
 
+  2007-03-21 Kieran Mansley
+  * netif.c, netif.h: Apply patch#4197 with some changes (originator: rireland@hmgsl.com). 
+    Provides callback on netif up/down state change.
+
   2007-03-11 Frédéric Bernon, Mace Gael, Steve Reynolds
   * sockets.h, sockets.c, api.h, api_lib.c, api_msg.h, api_msg.c, igmp.h, igmp.c,
     ip.c, netif.h, tcpip.c, opt.h:
diff --git a/src/core/netif.c b/src/core/netif.c
index b1e2bc18..5ec5a283 100644
--- a/src/core/netif.c
+++ b/src/core/netif.c
@@ -79,6 +79,10 @@ netif_add(struct netif *netif, struct ip_addr *ipaddr, struct ip_addr *netmask,
   /* netif not under DHCP control by default */
   netif->dhcp = NULL;
 #endif
+#if LWIP_NETIF_CALLBACK
+  netif->status_callback = NULL;
+#endif /* LWIP_NETIF_CALLBACK */
+
   /* remember netif specific state information data */
   netif->state = state;
   netif->num = netifnum++;
@@ -287,10 +291,17 @@ netif_set_default(struct netif *netif)
  */ 
 void netif_set_up(struct netif *netif)
 {
-  netif->flags |= NETIF_FLAG_UP;
+  if ( !(netif->flags & NETIF_FLAG_UP )) {
+    netif->flags |= NETIF_FLAG_UP;
+    
 #if LWIP_SNMP
-  snmp_get_sysuptime(&netif->ts);
+    snmp_get_sysuptime(&netif->ts);
 #endif
+#if LWIP_NETIF_CALLBACK
+    if ( netif->status_callback )
+      (netif->status_callback)( netif );
+#endif /* LWIP_NETIF_CALLBACK */
+  }
 }
 
 /**
@@ -311,10 +322,18 @@ u8_t netif_is_up(struct netif *netif)
  */ 
 void netif_set_down(struct netif *netif)
 {
-  netif->flags &= ~NETIF_FLAG_UP;
+  if ( netif->flags & NETIF_FLAG_UP )
+    {
+      netif->flags &= ~NETIF_FLAG_UP;
 #if LWIP_SNMP
-  snmp_get_sysuptime(&netif->ts);
+      snmp_get_sysuptime(&netif->ts);
 #endif
+      
+#if LWIP_NETIF_CALLBACK
+      if ( netif->status_callback )
+        (netif->status_callback)( netif );
+#endif /* LWIP_NETIF_CALLBACK */
+    }
 }
 
 void
@@ -323,3 +342,15 @@ netif_init(void)
   netif_list = netif_default = NULL;
 }
 
+
+#if LWIP_NETIF_CALLBACK
+/**
+ * Set callback to be called when interface is brought up/down
+ */
+void netif_set_status_callback( struct netif *netif, void (* status_callback)(struct netif *netif ))
+{
+    if ( netif )
+        netif->status_callback = status_callback;
+}
+#endif /* LWIP_NETIF_CALLBACK */
+
diff --git a/src/include/lwip/netif.h b/src/include/lwip/netif.h
index 4e58e734..9c86f8e5 100644
--- a/src/include/lwip/netif.h
+++ b/src/include/lwip/netif.h
@@ -90,6 +90,11 @@ struct netif {
    *  to send a packet on the interface. This function outputs
    *  the pbuf as-is on the link medium. */
   err_t (* linkoutput)(struct netif *netif, struct pbuf *p);
+#if LWIP_NETIF_CALLBACK
+  /** This function is called when the netif state is set to up or down
+   */
+  void (* status_callback)(struct netif *netif);
+#endif /* end, LWIP_NETIF_CALLBACK */
   /** This field can be set by the device driver and could point
    *  to state information for the device. */
   void *state;
@@ -165,5 +170,11 @@ void netif_set_gw(struct netif *netif, struct ip_addr *gw);
 void netif_set_up(struct netif *netif);
 void netif_set_down(struct netif *netif);
 u8_t netif_is_up(struct netif *netif);
+#if LWIP_NETIF_CALLBACK
+/*
+ * Set callback to be called when interface is brought up/down
+ */
+void netif_set_status_callback( struct netif *netif, void (* status_callback)(struct netif *netif ));
+#endif	/* LWIP_NETIF_CALLBACK */
 
 #endif /* __LWIP_NETIF_H__ */