diff --git a/src/www/services_dhcp.php b/src/www/services_dhcp.php
index ebfea9809..a54824242 100644
--- a/src/www/services_dhcp.php
+++ b/src/www/services_dhcp.php
@@ -139,6 +139,16 @@ if ($_SERVER['REQUEST_METHOD'] === 'GET') {
         $savemsg = gettext("The DHCP Server can only be enabled on interfaces configured with static IP addresses") . ".<br/><br/>" . gettext("Only interfaces configured with a static IP will be shown") . ".";
     }
 
+    /* If no interface is provided, choose first one from interfaces */
+    if (!isset($if)) {
+        foreach ($config['interfaces'] as $if_id => $intf) {
+            if (!empty($intf['enable']) && is_ipaddrv4($intf['ipaddr'])) {
+                $if = $if_id;
+                break;
+            }
+        }
+    }
+
     if (empty($config['dhcpd'][$if])) {
         $config['dhcpd'][$if] = array();
     }
@@ -153,15 +163,6 @@ if ($_SERVER['REQUEST_METHOD'] === 'GET') {
         $act = null;
     }
 
-    /* If no interface is provided, choose first one from interfaces */
-    if (!isset($if)) {
-        foreach ($config['interfaces'] as $if_id => $intf) {
-            if (!empty($intf['enable']) && is_ipaddrv4($intf['ipaddr'])) {
-                $if = $if_id;
-                break;
-            }
-        }
-    }
     // point to source of data (pool or main dhcp section)
     if (isset($pool)) {
         $dhcpdconf = &$a_pools[$pool];
diff --git a/src/www/services_dhcp_edit.php b/src/www/services_dhcp_edit.php
index 686c718bf..4e1da1d37 100644
--- a/src/www/services_dhcp_edit.php
+++ b/src/www/services_dhcp_edit.php
@@ -45,7 +45,7 @@ if ($_SERVER['REQUEST_METHOD'] === 'GET') {
         header("Location: services_dhcp.php");
         exit;
     }
-    if (!empty($config['dhcpd'][$if]['staticmap'][$_GET['id']])) {
+    if (isset($if) && isset($_GET['id']) && !empty($config['dhcpd'][$if]['staticmap'][$_GET['id']])) {
         $id = $_GET['id'];
     }
 
@@ -56,7 +56,7 @@ if ($_SERVER['REQUEST_METHOD'] === 'GET') {
       'ddnsdomainprimary', 'ddnsdomainkeyname', 'ddnsdomainkey', 'ddnsupdate', 'ntp1', 'ntp2', 'tftp', 'ipaddr',
       'winsserver', 'dnsserver');
     foreach ($config_copy_fieldnames as $fieldname) {
-        if (isset($config['dhcpd'][$if]['staticmap'][$id][$fieldname])) {
+        if (isset($if) && isset($id) && isset($config['dhcpd'][$if]['staticmap'][$id][$fieldname])) {
             $pconfig[$fieldname] = $config['dhcpd'][$if]['staticmap'][$id][$fieldname];
         } elseif (isset($_GET[$fieldname])) {
             $pconfig[$fieldname] = $_GET[$fieldname];
diff --git a/src/www/services_dhcpv6.php b/src/www/services_dhcpv6.php
index fec7f90cc..f55fd9b27 100644
--- a/src/www/services_dhcpv6.php
+++ b/src/www/services_dhcpv6.php
@@ -74,7 +74,7 @@ if ($_SERVER['REQUEST_METHOD'] === 'GET') {
           "IP addresses. Only interfaces configured with a static IP will be shown."
         );
         foreach ($config['interfaces'] as $if_id => $intf) {
-            if (!empty($intf['enable']) && is_ipaddrv6($intf['ipaddrv6']) && !is_linklocal($oc['ipaddrv6'])) {
+            if (!empty($intf['enable']) && isset($intf['ipaddrv6']) && is_ipaddrv6($intf['ipaddrv6']) && !is_linklocal($intf['ipaddrv6'])) {
                 $if = $if_id;
                 break;
             }
@@ -445,7 +445,7 @@ include("head.inc");
         /* active tabs */
         $tab_array_main = array();
         foreach ($config['interfaces'] as $if_id => $intf) {
-            if (!empty($intf['enable']) && is_ipaddrv6($intf['ipaddrv6'])) {
+            if (!empty($intf['enable']) && isset($intf['ipaddrv6']) && is_ipaddrv6($intf['ipaddrv6'])) {
                 $ifname = !empty($intf['descr']) ? htmlspecialchars($intf['descr']) : strtoupper($if_id);
                 if ($if_id == $if) {
                     $tab_array_main[] = array($ifname, true, "services_dhcpv6.php?if={$if_id}");
@@ -815,7 +815,7 @@ include("head.inc");
                       foreach ($config['dhcpdv6'][$if]['staticmap'] as $mapent): ?>
                     <tr>
                       <td><?=htmlspecialchars($mapent['duid']);?></td>
-                      <td><?=htmlspecialchars($mapent['ipaddrv6']);?></td>
+                      <td><?=isset($mapent['ipaddrv6']) ? htmlspecialchars($mapent['ipaddrv6']) : "";?></td>
                       <td><?=htmlspecialchars($mapent['hostname']);?></td>
                       <td><?=htmlspecialchars($mapent['descr']);?></td>
                       <td>
diff --git a/src/www/services_dhcpv6_edit.php b/src/www/services_dhcpv6_edit.php
index ece2e9807..3b79b01d3 100644
--- a/src/www/services_dhcpv6_edit.php
+++ b/src/www/services_dhcpv6_edit.php
@@ -37,7 +37,6 @@ function staticmapcmp($a, $b)
 }
 
 
-
 if ($_SERVER['REQUEST_METHOD'] === 'GET') {
     // handle identifiers and action
     if (!empty($_GET['if']) && !empty($config['interfaces'][$_GET['if']])) {
@@ -46,7 +45,7 @@ if ($_SERVER['REQUEST_METHOD'] === 'GET') {
         header("Location: services_dhcpv6.php");
         exit;
     }
-    if (!empty($config['dhcpdv6'][$if]['staticmap'][$_GET['id']])) {
+    if (isset($if) && isset($_GET['id']) && !empty($config['dhcpdv6'][$if]['staticmap'][$_GET['id']])) {
         $id = $_GET['id'];
     }
 
@@ -54,7 +53,7 @@ if ($_SERVER['REQUEST_METHOD'] === 'GET') {
     $pconfig = array();
     $config_copy_fieldnames = array('duid', 'hostname', 'ipaddrv6', 'filename' ,'rootpath' ,'descr');
     foreach ($config_copy_fieldnames as $fieldname) {
-        if (isset($config['dhcpdv6'][$if]['staticmap'][$id][$fieldname])) {
+        if (isset($if) && isset($id) && isset($config['dhcpdv6'][$if]['staticmap'][$id][$fieldname])) {
             $pconfig[$fieldname] = $config['dhcpdv6'][$if]['staticmap'][$id][$fieldname];
         } elseif (isset($_GET[$fieldname])) {
             $pconfig[$fieldname] = $_GET[$fieldname];