diff --git a/openbsd-compat/port-net.c b/openbsd-compat/port-net.c
index 617bffceb..d7d8c6fa1 100644
--- a/openbsd-compat/port-net.c
+++ b/openbsd-compat/port-net.c
@@ -209,8 +209,11 @@ sys_tun_open(int tun, int mode, char **ifname)
 {
 	struct ifreq ifr;
 	char name[100];
-	int fd = -1, sock, flag;
+	int fd = -1, sock;
 	const char *tunbase = "tun";
+#if defined(TUNSIFHEAD) && !defined(SSH_TUN_PREPEND_AF)
+	int flag;
+#endif
 
 	if (ifname != NULL)
 		*ifname = NULL;
@@ -247,8 +250,8 @@ sys_tun_open(int tun, int mode, char **ifname)
 	}
 
 	/* Turn on tunnel headers */
-	flag = 1;
 #if defined(TUNSIFHEAD) && !defined(SSH_TUN_PREPEND_AF)
+	flag = 1;
 	if (mode != SSH_TUNMODE_ETHERNET &&
 	    ioctl(fd, TUNSIFHEAD, &flag) == -1) {
 		debug("%s: ioctl(%d, TUNSIFHEAD, 1): %s", __func__, fd,