diff --git a/share/man/man4/tcp.4 b/share/man/man4/tcp.4
--- a/share/man/man4/tcp.4
+++ b/share/man/man4/tcp.4
@@ -892,7 +892,18 @@
 The initial value is used before an RTT measurement has been performed.
 .It Va rfc1323
 Implement the window scaling and timestamp options of RFC 1323/RFC 7323
-(default is true).
+(default is 1).
+Settings:
+.Bl -tag -compact
+.It 0
+Disable window scaling and timestamp option.
+.It 1
+Enable window scaling and timestamp option.
+.It 2
+Enable only window scaling.
+.It 3
+Enable only timestamp option.
+.El
 .It Va rfc3042
 Enable the Limited Transmit algorithm as described in RFC 3042.
 It helps avoid timeouts on lossy links and also when the congestion window
diff --git a/sys/netinet/tcp_subr.c b/sys/netinet/tcp_subr.c
--- a/sys/netinet/tcp_subr.c
+++ b/sys/netinet/tcp_subr.c
@@ -2280,8 +2280,20 @@
 	callout_init(&tp->t_timers->tt_2msl, 1);
 	callout_init(&tp->t_timers->tt_delack, 1);
 
-	if (V_tcp_do_rfc1323)
-		tp->t_flags = (TF_REQ_SCALE|TF_REQ_TSTMP);
+	switch (V_tcp_do_rfc1323) {
+		case 0:
+			break;
+		default:
+		case 1:
+			tp->t_flags = (TF_REQ_SCALE|TF_REQ_TSTMP);
+			break;
+		case 2:
+			tp->t_flags = TF_REQ_SCALE;
+			break;
+		case 3:
+			tp->t_flags = TF_REQ_TSTMP;
+			break;
+	}
 	if (V_tcp_do_sack)
 		tp->t_flags |= TF_SACK_PERMIT;
 	TAILQ_INIT(&tp->snd_holes);