diff --git a/src/etc/inc/interfaces.inc b/src/etc/inc/interfaces.inc
index d92d8c9f6..407be955c 100644
--- a/src/etc/inc/interfaces.inc
+++ b/src/etc/inc/interfaces.inc
@@ -3950,17 +3950,6 @@ function find_interface_networkv6($realif, $subnet = true, $ifconfig_details = n
     return "{$addr}/${net}";
 }
 
-function find_interface_ipv6_ll($realif, $ifconfig_details = null)
-{
-    $ifinfo = legacy_get_interface_addresses($realif, $ifconfig_details);
-
-    if (!isset($ifinfo['ipaddr6_ll'])) {
-        return null;
-    }
-
-    return $ifinfo['ipaddr6_ll'];
-}
-
 function ip_in_interface_alias_subnet($interface, $ipalias)
 {
     global $config;
@@ -4571,7 +4560,42 @@ function interfaces_addresses($interfaces, $as_subnet = false, $ifconfig_details
     return $result;
 }
 
-function interfaces_primary_address6($interface, $realif = null, $ifconfig_details = null)
+function interfaces_primary_address($interface, $realif = null, $ifconfig_details = null)
+{
+    $ifcfgip = $network = $subnetbits = null;
+
+    if ($realif === null) {
+        $realif = get_real_interface($interface);
+    }
+
+    $interfaces_a = config_read_array('interfaces');
+
+    foreach (interfaces_addresses($realif, true, $ifconfig_details) as $tmpaddr => $info) {
+        if ($info['family'] != 'inet') {
+            continue;
+        }
+
+        $addrparts = explode('/', $tmpaddr);
+
+        foreach (config_read_array('virtualip', 'vip') as $vip) {
+            if ($vip['interface'] == $interface && $vip['mode'] == 'ipalias' && strpos($vip['subnet'], ':') === false) {
+                 /* matching alias cannot be primary address */
+                if ($vip['subnet'] == $addrparts[0]) {
+                    continue 2;
+                }
+            }
+        }
+
+        $network = gen_subnet($addrparts[0], $addrparts[1]) . "/{$addrparts[1]}";
+        $subnetbits = $addrparts[1];
+        $ifcfgip = $addrparts[0];
+        break; /* all done */
+    }
+
+    return [ $ifcfgip, $network, $subnetbits ];
+}
+
+function interfaces_primary_address6($interface, $realif = null, $ifconfig_details = null, $linklocal = false)
 {
     $ifcfgipv6 = $networkv6 = $subnetbitsv6 = null;
 
@@ -4586,7 +4610,7 @@ function interfaces_primary_address6($interface, $realif = null, $ifconfig_detai
             continue;
         }
 
-        if (!isset($interfaces_a[$interface]['dhcp6prefixonly'])) {
+        if (!isset($interfaces_a[$interface]['dhcp6prefixonly']) && !$linklocal) {
             if ($info['scope']) {
                 continue;
             }
@@ -4614,8 +4638,16 @@ function interfaces_primary_address6($interface, $realif = null, $ifconfig_detai
         $networkv6 = gen_subnetv6($addrparts[0], $addrparts[1]) . "/{$addrparts[1]}";
         $subnetbitsv6 = $addrparts[1];
         $ifcfgipv6 = $addrparts[0];
+        if ($linklocal) {
+            $ifcfgipv6 .= "%{$realif}";
+        }
         break; /* all done */
     }
 
     return [ $ifcfgipv6, $networkv6, $subnetbitsv6 ];
 }
+
+function interfaces_linklocal_address6($interface, $realif = null, $ifconfig_details = null)
+{
+    return interfaces_primary_address6($interface, $realif, $ifconfig_details, true);
+}
diff --git a/src/etc/inc/plugins.inc.d/dpinger.inc b/src/etc/inc/plugins.inc.d/dpinger.inc
index 3f151d64c..3575f8d42 100644
--- a/src/etc/inc/plugins.inc.d/dpinger.inc
+++ b/src/etc/inc/plugins.inc.d/dpinger.inc
@@ -175,14 +175,13 @@ function dpinger_configure_do($verbose = false, $gwname = null)
         } elseif ($gateway['ipprotocol'] == "inet6") { // This is an IPv6 gateway...
             if (is_linklocal($gateway['monitor'])) {
                 /* link local monitor needs a link local address for the "src" part */
-                $gwifip = find_interface_ipv6_ll($gateway['if'], $ifconfig_details);
+                $gwifip = interfaces_linklocal_address6($gateway['if'], null, $ifconfig_details);
             } else {
-                /* monitor is a routable address, so use a routable address for the "src" part */
-                $gwifip = find_interface_ipv6($gateway['if'], $ifconfig_details);
+                $gwifip = interfaces_primary_address6($gateway['if'], null, $ifconfig_details);
             }
 
-            if (!is_ipaddrv6($gwifip)) {
-                log_error(sprintf('The %s IPv6 gateway address is invalid, skipping.', $name));
+            if (empty($gwifip)) {
+                log_error(sprintf('The %s IPv6 gateway address could not be found, skipping.', $name));
                 continue;
             }
 
@@ -196,9 +195,6 @@ function dpinger_configure_do($verbose = false, $gwname = null)
             if (is_linklocal($gateway['gateway']) && strpos($gateway['gateway'], '%') === false) {
                 $gateway['gateway'] .= "%{$gateway['if']}";
             }
-            if (is_linklocal($gwifip) && strpos($gwifip, '%') === false) {
-                $gwifip .= "%{$gateway['if']}";
-            }
 
             /* flush the monitor unconditionally */
             if (is_ipaddrv6($gateway['gateway']) && $gateway['monitor'] != $gateway['gateway']) {
diff --git a/src/etc/inc/plugins.inc.d/unbound.inc b/src/etc/inc/plugins.inc.d/unbound.inc
index d9144fe6d..0ffe07f23 100644
--- a/src/etc/inc/plugins.inc.d/unbound.inc
+++ b/src/etc/inc/plugins.inc.d/unbound.inc
@@ -513,11 +513,8 @@ function unbound_add_host_entries($ifconfig_details = null)
             continue;
         }
 
-        $realifv4 = get_real_interface($interface);
-        $realifv6 = get_real_interface($interface, 'inet6');
-
-        $laddr = find_interface_ip($realifv4, $ifconfig_details);
-        if (is_ipaddrv4($laddr)) {
+        list ($laddr) = interfaces_primary_address($interface, null, $ifconfig_details);
+        if (!empty($laddr)) {
             $domain = $config['system']['domain'];
             if (isset($config['dhcpd'][$interface]['enable']) && !empty($config['dhcpd'][$interface]['domain'])) {
                 $domain = $config['dhcpd'][$interface]['domain'];
@@ -526,8 +523,8 @@ function unbound_add_host_entries($ifconfig_details = null)
             $unbound_entries .= "local-data: \"{$config['system']['hostname']}.{$domain} A {$laddr}\"\n";
             $unbound_entries .= "local-data: \"{$config['system']['hostname']} A {$laddr}\"\n";
         }
-        $laddr6 = find_interface_ipv6($realifv6, $ifconfig_details);
-        if (is_ipaddrv6($laddr6)) {
+        list ($laddr6) = interfaces_primary_address6($interface, null, $ifconfig_details);
+        if (!empty($laddr6)) {
             $domain = $config['system']['domain'];
             if (isset($config['dhcpdv6'][$interface]['enable']) && !empty($config['dhcpdv6'][$interface]['domain'])) {
                 $domain = $config['dhcpdv6'][$interface]['domain'];
@@ -537,8 +534,10 @@ function unbound_add_host_entries($ifconfig_details = null)
             $unbound_entries .= "local-data: \"{$config['system']['hostname']} AAAA {$laddr6}\"\n";
         }
         if (empty($config['unbound']['noreglladdr6'])) {
-            $lladdr6 = find_interface_ipv6_ll($realifv6, $ifconfig_details);
-            if (is_ipaddrv6($lladdr6)) {
+            list ($lladdr6) = interfaces_linklocal_address6($interface, null, $ifconfig_details);
+            if (!empty($lladdr6)) {
+                /* cannot embed scope */
+                $lladdr6 = explode('%', $lladdr6)[0];
                 $domain = $config['system']['domain'];
                 if (isset($config['dhcpdv6'][$interface]['enable']) && !empty($config['dhcpdv6'][$interface]['domain'])) {
                     $domain = $config['dhcpdv6'][$interface]['domain'];
diff --git a/src/etc/rc.filter_synchronize b/src/etc/rc.filter_synchronize
index bd3f38f67..323b86890 100755
--- a/src/etc/rc.filter_synchronize
+++ b/src/etc/rc.filter_synchronize
@@ -2,35 +2,35 @@
 <?php
 
 /*
-    Copyright (C) 2016 Deciso B.V.
-    Copyright (C) 2004-2006 Scott Ullrich <sullrich@gmail.com>
-    Copyright (C) 2005 Bill Marquette <bill.marquette@gmail.com>
-    Copyright (C) 2006 Peter Allgeyer <allgeyer@web.de>
-    Copyright (C) 2008 Ermal Luçi
-    Copyright (C) 2003-2004 Manuel Kasper <mk@neon1.net>
-    All rights reserved.
-
-    Redistribution and use in source and binary forms, with or without
-    modification, are permitted provided that the following conditions are met:
-
-    1. Redistributions of source code must retain the above copyright notice,
-       this list of conditions and the following disclaimer.
-
-    2. Redistributions in binary form must reproduce the above copyright
-       notice, this list of conditions and the following disclaimer in the
-       documentation and/or other materials provided with the distribution.
-
-    THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
-    INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
-    AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
-    AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
-    OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
-    SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
-    INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
-    CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
-    ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
-    POSSIBILITY OF SUCH DAMAGE.
-*/
+ * Copyright (C) 2016 Deciso B.V.
+ * Copyright (C) 2004-2006 Scott Ullrich <sullrich@gmail.com>
+ * Copyright (C) 2005 Bill Marquette <bill.marquette@gmail.com>
+ * Copyright (C) 2006 Peter Allgeyer <allgeyer@web.de>
+ * Copyright (C) 2008 Ermal Luçi
+ * Copyright (C) 2003-2004 Manuel Kasper <mk@neon1.net>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
+ * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
+ * AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
+ * OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
 
 require_once("config.inc");
 require_once("filter.inc");
@@ -187,7 +187,7 @@ function carp_sync_xml($url, $username, $password, $sections, $debug)
         foreach($transport_data['dhcpd'] as $dhcpif => $dhcpifconf) {
             if (isset($dhcpifconf['failover_peerip']) && $dhcpifconf['failover_peerip'] != '') {
                 $int = guess_interface_from_ip($dhcpifconf['failover_peerip']);
-                $intip = find_interface_ip($int);
+                $intip = interfaces_primary_address($int);
                 $transport_data['dhcpd'][$dhcpif]['failover_peerip'] = $intip;
             }
         }
diff --git a/src/www/diag_ping.php b/src/www/diag_ping.php
index 1e015a8f2..7a00f4ef1 100644
--- a/src/www/diag_ping.php
+++ b/src/www/diag_ping.php
@@ -58,11 +58,10 @@ if ($_SERVER['REQUEST_METHOD'] === 'GET') {
                 break;
             case 'ipv6-ll':
                 $command .= '6';
-                $realif = get_real_interface($pconfig['interface'], 'inet6');
-                $ifaddr = find_interface_ipv6_ll($realif) . "%{$realif}";
+                list ($ifaddr) = interfaces_linklocal_address6($pconfig['interface']);
                 break;
             default:
-                $ifaddr = find_interface_ip(get_real_interface($pconfig['interface']));
+                list ($ifaddr) = interfaces_primary_address($pconfig['interface']);
                 break;
         }
         $srcip = '';
diff --git a/src/www/diag_testport.php b/src/www/diag_testport.php
index 984adb306..b04491279 100644
--- a/src/www/diag_testport.php
+++ b/src/www/diag_testport.php
@@ -75,16 +75,15 @@ if ($_SERVER['REQUEST_METHOD'] === 'GET') {
         switch ($pconfig['ipprotocol']) {
             case 'ipv6':
                 list ($ifaddr) = interfaces_primary_address6($pconfig['interface']);
-                $nc_args .= " -6";
+                $nc_args .= ' -6';
                 break;
             case 'ipv6-ll':
-                $realif = get_real_interface($pconfig['interface'], 'inet6');
-                $ifaddr = find_interface_ipv6_ll($realif) . "%{$realif}";
-                $nc_args .= " -6";
+                list ($ifaddr) = interfaces_linklocal_address6($pconfig['interface']);
+                $nc_args .= ' -6';
                 break;
             default:
-                $ifaddr = find_interface_ip(get_real_interface($pconfig['interface']));
-                $nc_args .= " -4";
+                list ($ifaddr) = interfaces_primary_address($pconfig['interface']);
+                $nc_args .= ' -4';
                 break;
         }
 
@@ -92,7 +91,7 @@ if ($_SERVER['REQUEST_METHOD'] === 'GET') {
             $nc_args .= exec_safe(' -s %s ', $ifaddr);
         }
 
-        $cmd_action = exec_safe("/usr/bin/nc {$nc_args} %s %s", array($pconfig['host'], $pconfig['port']));
+        $cmd_action = "/usr/bin/nc {$nc_args} " . exec_safe('%s %s', [$pconfig['host'], $pconfig['port']]);
         $process = proc_open($cmd_action, array(array("pipe", "r"), array("pipe", "w"), array("pipe", "w")), $pipes);
         if (is_resource($process)) {
              $cmd_output = "# $cmd_action\n";
diff --git a/src/www/diag_traceroute.php b/src/www/diag_traceroute.php
index 097bb5b42..26818e619 100644
--- a/src/www/diag_traceroute.php
+++ b/src/www/diag_traceroute.php
@@ -77,7 +77,7 @@ if ($_SERVER['REQUEST_METHOD'] === 'GET') {
             list ($ifaddr) = interfaces_primary_address6($pconfig['interface']);
             $command .= '6';
         } else {
-            $ifaddr = find_interface_ip(get_real_interface($pconfig['interface']));
+            list ($ifaddr) = interfaces_primary_address($pconfig['interface']);
         }
 
         if (is_ipaddr($ifaddr) && (is_ipaddr($host) || is_hostname($host))) {