diff --git a/src/etc/rc.newwanipv6 b/src/etc/rc.newwanipv6
index 7a03d1652..7c3831a10 100755
--- a/src/etc/rc.newwanipv6
+++ b/src/etc/rc.newwanipv6
@@ -58,12 +58,26 @@ if (!isset($config['interfaces'][$interface]['enable'])) {
     return;
 }
 
+$interface_descr = convert_friendly_interface_to_friendly_descr($interface);
+
+/* make sure only one script runs at a time beyond this point */
+$fp = fopen('/tmp/newwanipv6_' . $argument, 'a+');
+if (!$fp || !flock($fp, LOCK_EX | LOCK_NB)) {
+    if ($force == 'yes') {
+        log_msg("Lost a forceful reload on {$interface_descr}[{$interface}]) due to previous lock", LOG_WARNING);
+    }
+    fclose($fp);
+    return;
+}
+
+/* wait for DAD to complete to avoid discarding tentative address */
+$dad_delay = (int)get_single_sysctl('net.inet6.ip6.dad_count');
+sleep($dad_delay + 1);
+
 /* this may be required to cleanse the DNS information no longer available */
 system_resolver_configure();
 
-$interface_descr = convert_friendly_interface_to_friendly_descr($interface);
 list ($ip) = interfaces_primary_address6($interface);
-
 if (!is_ipaddr($ip)) {
     /* interface is not ready */
     log_msg("Failed to detect IP for {$interface_descr}[{$interface}]", LOG_INFO);
diff --git a/src/opnsense/scripts/interfaces/rtsold_resolvconf.sh b/src/opnsense/scripts/interfaces/rtsold_resolvconf.sh
index 96ac162ba..bd32e051a 100755
--- a/src/opnsense/scripts/interfaces/rtsold_resolvconf.sh
+++ b/src/opnsense/scripts/interfaces/rtsold_resolvconf.sh
@@ -69,8 +69,5 @@ elif [ "${1}" = "-d" ]; then
 	/usr/local/sbin/ifctl -i ${ifname} -6rd
 fi
 
-# wait for DAD to complete to avoid tentative address
-sleep "$(($(sysctl -n net.inet6.ip6.dad_count) + 1))"
-
 # remove slaac suffix here to reload correct interface
 /usr/local/sbin/configctl -d interface newipv6 ${ifname%%:slaac}