diff --git a/core/net/ip/uip-nameserver.c b/core/net/ip/uip-nameserver.c
index 6ced6b91e..6e34346b0 100644
--- a/core/net/ip/uip-nameserver.c
+++ b/core/net/ip/uip-nameserver.c
@@ -56,8 +56,10 @@ typedef struct uip_nameserver_record {
   uint32_t lifetime;
 } uip_nameserver_record;
 
+#if UIP_NAMESERVER_POOL_SIZE > 1
 /** \brief Initialization flag */
 static uint8_t initialized = 0;
+#endif /* UIP_NAMESERVER_POOL_SIZE > 1 */
 
 /** \name List and memory block
  * @{
@@ -90,7 +92,7 @@ init(void)
 #endif /* UIP_NAMESERVER_POOL_SIZE > 1 */
 /*----------------------------------------------------------------------------*/
 void
-uip_nameserver_update(uip_ipaddr_t *nameserver, uint32_t lifetime)
+uip_nameserver_update(const uip_ipaddr_t *nameserver, uint32_t lifetime)
 {
 #if UIP_NAMESERVER_POOL_SIZE > 1
   register uip_nameserver_record *e;
diff --git a/core/net/ip/uip-nameserver.h b/core/net/ip/uip-nameserver.h
index 41dcf58c8..6acf62290 100644
--- a/core/net/ip/uip-nameserver.h
+++ b/core/net/ip/uip-nameserver.h
@@ -74,7 +74,7 @@
  *                     considered to remove an entry. Maximum is 0xFFFFFFFF which
  *                     is considered infinite.
  */
-void uip_nameserver_update(uip_ipaddr_t *nameserver, uint32_t lifetime);
+void uip_nameserver_update(const uip_ipaddr_t *nameserver, uint32_t lifetime);
 
 /**
  * \brief Get a Nameserver ip address given in RA