diff --git a/src/config.h b/src/config.h
index cb31eb6..91eb70f 100644
--- a/src/config.h
+++ b/src/config.h
@@ -46,6 +46,7 @@
 #define SOA_REFRESH 1200 /* SOA refresh default */
 #define SOA_RETRY 180 /* SOA retry default */
 #define SOA_EXPIRY 1209600 /* SOA expiry default */
+#define RA_INTERVAL 600 /* Send unsolicited RA's this often when not provoked. */
  
 /* compile-time options: uncomment below to enable or do eg.
    make COPTS=-DHAVE_BROKEN_RTC
diff --git a/src/radv.c b/src/radv.c
index 648568a..d0f4422 100644
--- a/src/radv.c
+++ b/src/radv.c
@@ -390,8 +390,8 @@ static int add_prefixes(struct in6_addr *local,  int prefix,
 		if (time > context->lease_time)
 		  {
 		    time = context->lease_time;
-		    if (time < 600u)
-		      time = 600;
+		    if (time < ((unsigned int)RA_INTERVAL))
+		      time = RA_INTERVAL;
 		  }
 
 		if (context->flags & CONTEXT_DEPRECATE)
@@ -572,8 +572,8 @@ static int iface_search(struct in6_addr *local,  int prefix,
 	  /* range 5 - 20 */
 	  context->ra_time = param->now + 5 + (rand16()/4400);
 	else
-	  /* range 450 - 600 */
-	  context->ra_time = param->now + 450 + (rand16()/440);
+	  /* range 3/4 - 1 times RA_INTERVAL */
+	  context->ra_time = param->now + (3 * RA_INTERVAL)/4 + ((RA_INTERVAL * (unsigned int)rand16()) >> 18);
 	
 	/* zero timers for other contexts on the same subnet, so they don't timeout 
 	   independently */