diff --git a/core/net/ip/tcpip.c b/core/net/ip/tcpip.c
index 6f2744785..1c75d1bc9 100644
--- a/core/net/ip/tcpip.c
+++ b/core/net/ip/tcpip.c
@@ -228,7 +228,7 @@ packet_input(void)
 #if UIP_TCP
 #if UIP_ACTIVE_OPEN
 struct uip_conn *
-tcp_connect(uip_ipaddr_t *ripaddr, uint16_t port, void *appstate)
+tcp_connect(const uip_ipaddr_t *ripaddr, uint16_t port, void *appstate)
 {
   struct uip_conn *c;
   
diff --git a/core/net/ip/tcpip.h b/core/net/ip/tcpip.h
index 3fd64bce8..8fb2ff526 100644
--- a/core/net/ip/tcpip.h
+++ b/core/net/ip/tcpip.h
@@ -165,7 +165,7 @@ CCIF void tcp_unlisten(uint16_t port);
  * memory could not be allocated for the connection.
  *
  */
-CCIF struct uip_conn *tcp_connect(uip_ipaddr_t *ripaddr, uint16_t port,
+CCIF struct uip_conn *tcp_connect(const uip_ipaddr_t *ripaddr, uint16_t port,
 				  void *appstate);
 
 /**
diff --git a/core/net/ip/uip.h b/core/net/ip/uip.h
index c3838318e..cb12f52ab 100644
--- a/core/net/ip/uip.h
+++ b/core/net/ip/uip.h
@@ -600,7 +600,7 @@ void uip_unlisten(uint16_t port);
  * or NULL if no connection could be allocated.
  *
  */
-struct uip_conn *uip_connect(uip_ipaddr_t *ripaddr, uint16_t port);
+struct uip_conn *uip_connect(const uip_ipaddr_t *ripaddr, uint16_t port);
 
 
 
diff --git a/core/net/ipv4/uip.c b/core/net/ipv4/uip.c
index 1c767e170..9668d1f2b 100644
--- a/core/net/ipv4/uip.c
+++ b/core/net/ipv4/uip.c
@@ -386,7 +386,7 @@ uip_init(void)
 /*---------------------------------------------------------------------------*/
 #if UIP_ACTIVE_OPEN
 struct uip_conn *
-uip_connect(uip_ipaddr_t *ripaddr, uint16_t rport)
+uip_connect(const uip_ipaddr_t *ripaddr, uint16_t rport)
 {
   register struct uip_conn *conn, *cconn;
 
diff --git a/core/net/ipv6/uip6.c b/core/net/ipv6/uip6.c
index a5d1db13c..c88822fbf 100644
--- a/core/net/ipv6/uip6.c
+++ b/core/net/ipv6/uip6.c
@@ -459,7 +459,7 @@ uip_init(void)
 /*---------------------------------------------------------------------------*/
 #if UIP_TCP && UIP_ACTIVE_OPEN
 struct uip_conn *
-uip_connect(uip_ipaddr_t *ripaddr, uint16_t rport)
+uip_connect(const uip_ipaddr_t *ripaddr, uint16_t rport)
 {
   register struct uip_conn *conn, *cconn;