diff --git a/share/man/man4/inet.4 b/share/man/man4/inet.4
--- a/share/man/man4/inet.4
+++ b/share/man/man4/inet.4
@@ -25,7 +25,7 @@
 .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 .\" SUCH DAMAGE.
 .\"
-.Dd September 8, 2022
+.Dd December 31, 2024
 .Dt INET 4
 .Os
 .Sh NAME
@@ -169,11 +169,11 @@
 .It Va accept_sourceroute
 Boolean: enable/disable accepting of source-routed IP packets (default false).
 .It Va allow_net0
-Boolean: allow use of addresses in 0.0.0.0/8 as endpoints,
-and allow forwarding of packets with these addresses.
+Boolean: allow forwarding of, and ICMP responses to, packets with addresses in
+0.0.0.0/8.
 .It Va allow_net240
-Boolean: allow use of addresses in 240.0.0.0/4 as endpoints,
-and allow forwarding of packets with these addresses.
+Boolean: allow forwarding of, and ICMP responses to, packets with addresses in
+240.0.0.0/4.
 .It Va curfrags
 Integer: Current number of IPv4 fragments across all reassembly queues
 in all VNETs (read-only).
diff --git a/sys/netinet/in.c b/sys/netinet/in.c
--- a/sys/netinet/in.c
+++ b/sys/netinet/in.c
@@ -102,13 +102,13 @@
 #define	V_ip_allow_net240		VNET(ip_allow_net240)
 SYSCTL_BOOL(_net_inet_ip, OID_AUTO, allow_net240,
 	CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(ip_allow_net240), 0,
-	"Allow use of Experimental addresses, aka Class E (240/4)");
+	"Allow forwarding of and ICMP response to Experimental addresses, aka Class E (240/4)");
 /* see https://datatracker.ietf.org/doc/draft-schoen-intarea-unicast-240 */
 
 VNET_DEFINE(bool, ip_allow_net0) = false;
 SYSCTL_BOOL(_net_inet_ip, OID_AUTO, allow_net0,
 	CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(ip_allow_net0), 0,
-	"Allow use of addresses in network 0/8");
+	"Allow forwarding of and ICMP response to addresses in network 0/8");
 /* see https://datatracker.ietf.org/doc/draft-schoen-intarea-unicast-0 */
 
 VNET_DEFINE(uint32_t, in_loopback_mask) = IN_LOOPBACK_MASK_DFLT;