diff --git a/core/net/ip/ip64-addr.c b/core/net/ip/ip64-addr.c
index 4d1fa378e..38ae04f1f 100644
--- a/core/net/ip/ip64-addr.c
+++ b/core/net/ip/ip64-addr.c
@@ -35,6 +35,10 @@
 #include <string.h>
 
 #define printf(...)
+
+static uip_ip6addr_t ip64_prefix = {{ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0xff, 0xff, 0, 0, 0, 0}};
+static uint8_t ip64_prefix_len = 96;
+
 /*---------------------------------------------------------------------------*/
 void
 ip64_addr_copy4(uip_ip4addr_t *dest, const uip_ip4addr_t *src)
@@ -56,20 +60,7 @@ ip64_addr_4to6(const uip_ip4addr_t *ipv4addr,
      addresses. It returns 0 if it failed to convert the address and
      non-zero if it could successfully convert the address. */
 
-  /* The IPv4 address is encoded as an IPv6-encoded IPv4 address in
-     the ::ffff:0000/24 prefix.*/
-  ipv6addr->u8[0] = 0;
-  ipv6addr->u8[1] = 0;
-  ipv6addr->u8[2] = 0;
-  ipv6addr->u8[3] = 0;
-  ipv6addr->u8[4] = 0;
-  ipv6addr->u8[5] = 0;
-  ipv6addr->u8[6] = 0;
-  ipv6addr->u8[7] = 0;
-  ipv6addr->u8[8] = 0;
-  ipv6addr->u8[9] = 0;
-  ipv6addr->u8[10] = 0xff;
-  ipv6addr->u8[11] = 0xff;
+  uip_ipaddr_copy(ipv6addr, &ip64_prefix);
   ipv6addr->u8[12] = ipv4addr->u8[0];
   ipv6addr->u8[13] = ipv4addr->u8[1];
   ipv6addr->u8[14] = ipv4addr->u8[2];
@@ -90,21 +81,7 @@ ip64_addr_6to4(const uip_ip6addr_t *ipv6addr,
      returns 0 if it failed to convert the address and non-zero if it
      could successfully convert the address. */
 
-  /* If the IPv6 address is an IPv6-encoded
-     IPv4 address (i.e. in the ::ffff:0/8 prefix), we simply use the
-     IPv4 addresses directly. */
-  if(ipv6addr->u8[0] == 0 &&
-     ipv6addr->u8[1] == 0 &&
-     ipv6addr->u8[2] == 0 &&
-     ipv6addr->u8[3] == 0 &&
-     ipv6addr->u8[4] == 0 &&
-     ipv6addr->u8[5] == 0 &&
-     ipv6addr->u8[6] == 0 &&
-     ipv6addr->u8[7] == 0 &&
-     ipv6addr->u8[8] == 0 &&
-     ipv6addr->u8[9] == 0 &&
-     ipv6addr->u8[10] == 0xff &&
-     ipv6addr->u8[11] == 0xff) {
+  if(ip64_addr_is_ip64(ipv6addr)) {
     ipv4addr->u8[0] = ipv6addr->u8[12];
     ipv4addr->u8[1] = ipv6addr->u8[13];
     ipv4addr->u8[2] = ipv6addr->u8[14];
@@ -121,3 +98,16 @@ ip64_addr_6to4(const uip_ip6addr_t *ipv6addr,
   return 0;
 }
 /*---------------------------------------------------------------------------*/
+int
+ip64_addr_is_ip64(const uip_ip6addr_t *ipv6addr)
+{
+  return uip_ipaddr_prefixcmp(ipv6addr, &ip64_prefix, ip64_prefix_len);
+}
+/*---------------------------------------------------------------------------*/
+void
+ip64_addr_set_prefix(const uip_ip6addr_t *prefix, uint8_t prefix_len)
+{
+  uip_ipaddr_copy(&ip64_prefix, prefix);
+  ip64_prefix_len = prefix_len;
+}
+/*---------------------------------------------------------------------------*/
diff --git a/core/net/ip/ip64-addr.h b/core/net/ip/ip64-addr.h
index 3027d846a..67f71b635 100644
--- a/core/net/ip/ip64-addr.h
+++ b/core/net/ip/ip64-addr.h
@@ -58,6 +58,9 @@ int ip64_addr_6to4(const uip_ip6addr_t *ipv6addr,
 int ip64_addr_4to6(const uip_ip4addr_t *ipv4addr,
 		   uip_ip6addr_t *ipv6addr);
 
+int ip64_addr_is_ip64(const uip_ip6addr_t *ipv6addr);
+
+void ip64_addr_set_prefix(const uip_ip6addr_t *prefix, uint8_t prefix_len);
 
 #endif /* IP64_ADDR_H */