Index: head/UPDATING
===================================================================
--- head/UPDATING
+++ head/UPDATING
@@ -26,6 +26,10 @@
 	world, or to merely disable the most expensive debugging functionality
 	at runtime, run "ln -s 'abort:false,junk:false' /etc/malloc.conf".)
 
+20201108:
+	Default value of net.add_addr_allfibs has been changed to 0.
+	If you have multi-fib configuration and rely on existence of all
+	interface routes in every fib, you need to set the above sysctl to 1.
 20201030:
 	The internal pre-processor in the calendar(1) program has been
 	extended to support more C pre-processor commands (e.g. #ifdef, #else,
Index: head/sys/net/route/route_ifaddrs.c
===================================================================
--- head/sys/net/route/route_ifaddrs.c
+++ head/sys/net/route/route_ifaddrs.c
@@ -61,7 +61,7 @@
  * By default, interface address routes are added to the fib of the interface.
  * Once set to non-zero, adds interface address route to all fibs.
  */
-VNET_DEFINE(u_int, rt_add_addr_allfibs) = 1;
+VNET_DEFINE(u_int, rt_add_addr_allfibs) = 0;
 SYSCTL_UINT(_net, OID_AUTO, add_addr_allfibs, CTLFLAG_RWTUN | CTLFLAG_VNET,
     &VNET_NAME(rt_add_addr_allfibs), 0, "");
 
Index: head/sys/net/route/route_tables.c
===================================================================
--- head/sys/net/route/route_tables.c
+++ head/sys/net/route/route_tables.c
@@ -183,6 +183,11 @@
 	new_rt_tables = mallocarray(num_tables * (AF_MAX + 1), sizeof(void *),
 	    M_RTABLE, M_WAITOK | M_ZERO);
 
+	if ((num_tables > 1) && (V_rt_add_addr_allfibs == 0))
+		printf("WARNING: Adding ifaddrs to all fibs has been turned off "
+			"by default. Consider tuning %s if needed\n",
+			"net.add_addr_allfibs");
+
 	/*
 	 * Current rt_tables layout:
 	 * fib0[af0, af1, af2, .., AF_MAX]fib1[af0, af1, af2, .., Af_MAX]..