diff --git a/ripd/ripd.h b/ripd/ripd.h
index 13a72a1..5c50c57 100644
--- a/ripd/ripd.h
+++ b/ripd/ripd.h
@@ -78,8 +78,18 @@
 #define RIP_ROUTE_REDISTRIBUTE           3
 #define RIP_ROUTE_INTERFACE              4
 
-/* RIP MD5 authentication. */
+/* RIPv2 special RTE family types */
+#define RIP_FAMILY_AUTH                  0xffff
+
+/* RIPv2 authentication types, for RIP_FAMILY_AUTH RTE's */
+#define RIP_NO_AUTH                0
+#define RIP_AUTH_DATA              1
+#define RIP_AUTH_SIMPLE_PASSWORD   2
+#define RIP_AUTH_MD5               3
+
+/* RIPv2 MD5 authentication. */
 #define RIP_AUTH_MD5_SIZE               16
+#define RIP_AUTH_MD5_COMPAT_SIZE        RIP_RTE_SIZE
 
 /* RIP structure. */
 struct rip 
@@ -237,10 +247,6 @@
   int ri_receive;
 
   /* RIPv2 authentication type. */
-#define RIP_NO_AUTH                0
-#define RIP_AUTH_DATA              1
-#define RIP_AUTH_SIMPLE_PASSWORD   2
-#define RIP_AUTH_MD5               3
   int auth_type;
 
   /* RIPv2 authentication string. */
@@ -249,6 +255,9 @@
   /* RIPv2 authentication key chain. */
   char *key_chain;
 
+  /* value to use for md5->auth_len */
+  u_int8_t md5_auth_len;
+
   /* Split horizon flag. */
   split_horizon_policy_t split_horizon;
   split_horizon_policy_t split_horizon_default;