diff --git a/share/man/man4/inet6.4 b/share/man/man4/inet6.4
--- a/share/man/man4/inet6.4
+++ b/share/man/man4/inet6.4
@@ -29,7 +29,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd November 12, 2021
+.Dd February 22, 2023
 .Dt INET6 4
 .Os
 .Sh NAME
@@ -185,7 +185,9 @@
 .Tn ICMPv6
 message protocol is accessible from a raw socket.
 .Ss MIB Variables
-A number of variables are implemented in the net.inet6 branch of the
+A number of variables are implemented in the
+.Va net.inet6
+branch of the
 .Xr sysctl 3
 MIB.
 In addition to the variables supported by the transport protocols
@@ -341,6 +343,11 @@
 .Dv AF_INET6
 sockets.
 Defaults to on.
+.It Va ip6.log_cannot_forward
+Boolean: log packets that can't be forwarded because of unspecified source
+address or destination address beyond the scope of the source address as
+described in RFC4443.
+Enabled by default.
 .It Va ip6.source_address_validation
 Boolean: perform source address validation for packets destined for the local
 host.
@@ -440,6 +447,15 @@
 .Xr ip6 4 ,
 .Xr tcp 4 ,
 .Xr udp 4
+.Rs
+.%A A. Conta
+.%A S. Deering
+.%A M. Gupta
+.%T "Internet Control Message Protocol (ICMPv6) for the Internet" \
+    "Protocol Version 6 (IPv6) Specification"
+.%R RFC 4443
+.%D March 2006
+.Re
 .Sh STANDARDS
 .Rs
 .%A Tatsuya Jinmei
diff --git a/sys/netinet6/in6_proto.c b/sys/netinet6/in6_proto.c
--- a/sys/netinet6/in6_proto.c
+++ b/sys/netinet6/in6_proto.c
@@ -179,6 +179,7 @@
 #endif
 VNET_DEFINE(int, nd6_onlink_ns_rfc4861) = 0;/* allow 'on-link' nd6 NS
 					     * (RFC 4861) */
+VNET_DEFINE(bool, ip6_log_cannot_forward) = 1;
 
 /* icmp6 */
 /*
@@ -342,6 +343,10 @@
 	&VNET_NAME(ip6stealth), 0,
 	"Forward IPv6 packets without decrementing their TTL");
 #endif
+SYSCTL_BOOL(_net_inet6_ip6, OID_AUTO,
+	log_cannot_forward, CTLFLAG_VNET | CTLFLAG_RW,
+	&VNET_NAME(ip6_log_cannot_forward), 1,
+	"Log packets that cannot be forwarded");
 
 /* net.inet6.icmp6 */
 SYSCTL_INT(_net_inet6_icmp6, ICMPV6CTL_REDIRACCEPT, rediraccept,
diff --git a/sys/netinet6/ip6_forward.c b/sys/netinet6/ip6_forward.c
--- a/sys/netinet6/ip6_forward.c
+++ b/sys/netinet6/ip6_forward.c
@@ -114,7 +114,8 @@
 	    IN6_IS_ADDR_UNSPECIFIED(&ip6->ip6_src)) {
 		IP6STAT_INC(ip6s_cantforward);
 		/* XXX in6_ifstat_inc(rt->rt_ifp, ifs6_in_discard) */
-		if (V_ip6_log_time + V_ip6_log_interval < time_uptime) {
+		if (V_ip6_log_cannot_forward &&
+		    (V_ip6_log_time + V_ip6_log_interval < time_uptime)) {
 			V_ip6_log_time = time_uptime;
 			log(LOG_DEBUG,
 			    "cannot forward "
@@ -221,7 +222,8 @@
 		IP6STAT_INC(ip6s_badscope);
 		in6_ifstat_inc(nh->nh_ifp, ifs6_in_discard);
 
-		if (V_ip6_log_time + V_ip6_log_interval < time_uptime) {
+		if (V_ip6_log_cannot_forward &&
+		    (V_ip6_log_time + V_ip6_log_interval < time_uptime)) {
 			V_ip6_log_time = time_uptime;
 			log(LOG_DEBUG,
 			    "cannot forward "
diff --git a/sys/netinet6/ip6_mroute.c b/sys/netinet6/ip6_mroute.c
--- a/sys/netinet6/ip6_mroute.c
+++ b/sys/netinet6/ip6_mroute.c
@@ -1099,7 +1099,8 @@
 	 */
 	if (IN6_IS_ADDR_UNSPECIFIED(&ip6->ip6_src)) {
 		IP6STAT_INC(ip6s_cantforward);
-		if (V_ip6_log_time + V_ip6_log_interval < time_uptime) {
+		if (V_ip6_log_cannot_forward &&
+		    (V_ip6_log_time + V_ip6_log_interval < time_uptime)) {
 			V_ip6_log_time = time_uptime;
 			log(LOG_DEBUG,
 			    "cannot forward "
diff --git a/sys/netinet6/ip6_var.h b/sys/netinet6/ip6_var.h
--- a/sys/netinet6/ip6_var.h
+++ b/sys/netinet6/ip6_var.h
@@ -339,6 +339,9 @@
 #define	V_nd6_ignore_ipv6_only_ra	VNET(nd6_ignore_ipv6_only_ra)
 #endif
 
+VNET_DECLARE(bool, ip6_log_cannot_forward);
+#define	V_ip6_log_cannot_forward	VNET(ip6_log_cannot_forward)
+
 extern struct	pr_usrreqs rip6_usrreqs;
 struct sockopt;