diff --git a/share/man/man7/tuning.7 b/share/man/man7/tuning.7
index 5c44068a3f6f..741ad7990ec0 100644
--- a/share/man/man7/tuning.7
+++ b/share/man/man7/tuning.7
@@ -469,6 +469,7 @@ These extensions should be enabled and the TCP buffer size should be set
 to a value larger than 65536 in order to obtain good performance out of
 certain types of network links; specifically, gigabit WAN links and
 high-latency satellite links.
+RFC1323 support is enabled by default.
 .Pp
 The
 .Va net.inet.tcp.always_keepalive