diff --git a/CHANGELOG b/CHANGELOG
index 5fa50a18..e7b974b4 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -45,6 +45,10 @@ HISTORY
 
   ++ Bug fixes:
   
+  2007-03-06 Simon Goldschmidt
+  * tcpip.c: Initialize dhcp timers in tcpip_thread (if LWIP_DHCP) to protect
+    the stack from concurrent access.
+
   2007-03-06 Frédéric Bernon, Dmitry Potapov
   * tcpip.c, ip_frag.c, ethernetif.c: Fix some build problems, and a redundancy
     call to "lwip_stats.link.recv++;" in low_level_input() & ethernetif_input().
diff --git a/src/api/tcpip.c b/src/api/tcpip.c
index 7c0f8d24..129f5fed 100644
--- a/src/api/tcpip.c
+++ b/src/api/tcpip.c
@@ -102,6 +102,24 @@ arp_timer(void *arg)
   sys_timeout( ARP_TMR_INTERVAL, arp_timer, NULL);
 }
 
+#if LWIP_DHCP
+static void
+dhcp_timer_coarse(void *arg)
+{
+  LWIP_DEBUGF(TCPIP_DEBUG, ("tcpip: dhcp_coarse_tmr()\n"));
+  dhcp_coarse_tmr();
+  sys_timeout(DHCP_COARSE_TIMER_SECS*1000, dhcp_timer_coarse, NULL);
+}
+
+static void
+dhcp_timer_fine(void *arg)
+{
+  LWIP_DEBUGF(TCPIP_DEBUG, ("tcpip: dhcp_fine_tmr()\n"));
+  dhcp_fine_tmr();
+  sys_timeout(DHCP_FINE_TIMER_MSECS, dhcp_timer_fine, NULL);
+}
+#endif
+
 #if ETHARP_TCPIP_ETHINPUT
 static void
 ethernet_input(struct pbuf *p, struct netif *netif)
@@ -146,6 +164,10 @@ tcpip_thread(void *arg)
   sys_timeout( IP_TMR_INTERVAL, ip_timer, NULL);
 #endif
   sys_timeout( ARP_TMR_INTERVAL, arp_timer, NULL);
+#if LWIP_DHCP
+  sys_timeout(DHCP_COARSE_TIMER_SECS*1000, dhcp_timer_coarse, NULL);
+  sys_timeout(DHCP_FINE_TIMER_MSECS, dhcp_timer_fine, NULL);
+#endif
 
   if (tcpip_init_done != NULL) {
     tcpip_init_done(tcpip_init_done_arg);