diff --git a/ajax/networking/get_netcfg.php b/ajax/networking/get_netcfg.php
index 757a9c1e..5b7bf2e1 100644
--- a/ajax/networking/get_netcfg.php
+++ b/ajax/networking/get_netcfg.php
@@ -18,14 +18,14 @@ if (isset($interface)) {
     } else {
         $arrRange = explode(",", $conf['dhcp-range'][0]);
     }
-    $dhcpdata['RangeStart'] = $arrRange[0];
-    $dhcpdata['RangeEnd'] = $arrRange[1];
-    $dhcpdata['RangeMask'] = $arrRange[2];
-    $dhcpdata['leaseTime'] = $arrRange[3];
-    $dhcpHost = $conf["dhcp-host"];
+    $dhcpdata['RangeStart'] = $arrRange[0] ?? null;
+    $dhcpdata['RangeEnd'] = $arrRange[1] ?? null;
+    $dhcpdata['RangeMask'] = $arrRange[2] ?? null;
+    $dhcpdata['leaseTime'] = $arrRange[3] ?? null;
+    $dhcpHost = $conf["dhcp-host"] ?? null;
     $dhcpHost = empty($dhcpHost) ? [] : $dhcpHost;
     $dhcpdata['dhcpHost'] = is_array($dhcpHost) ? $dhcpHost : [ $dhcpHost ];
-    $upstreamServers = is_array($conf['server']) ? $conf['server'] : [ $conf['server'] ];
+    $upstreamServers = is_array($conf['server'] ?? null) ? $conf['server'] : [ $conf['server'] ?? '' ];
     $dhcpdata['upstreamServersEnabled'] = empty($conf['server']) ? false: true;
     $dhcpdata['upstreamServers'] = array_filter($upstreamServers);
     preg_match('/([0-9]*)([a-z])/i', $dhcpdata['leaseTime'], $arrRangeLeaseTime);
@@ -35,10 +35,10 @@ if (isset($interface)) {
         $arrDns = explode(",", $conf['dhcp-option']);
         if ($arrDns[0] == '6') {
             if (count($arrDns) > 1) {
-                $dhcpdata['DNS1'] = $arrDns[1];
+                $dhcpdata['DNS1'] = $arrDns[1] ?? null;
             }
             if (count($arrDns) > 2) {
-                $dhcpdata['DNS2'] = $arrDns[2];
+                $dhcpdata['DNS2'] = $arrDns[2] ?? null;
             }
         }
     }
@@ -53,13 +53,15 @@ if (isset($interface)) {
     preg_match('/fallback\sstatic_'.$interface.'/', $matched[0], $fallback);
     preg_match('/(?:no)?gateway/', $matched[0], $gateway);
     preg_match('/nohook\swpa_supplicant/', $matched[0], $nohook_wpa_supplicant);
-    $dhcpdata['Metric'] = $metric[1];
-    $dhcpdata['StaticIP'] = strpos($static_ip[1],'/') ?  substr($static_ip[1], 0, strpos($static_ip[1],'/')) : $static_ip[1];
-    $dhcpdata['SubnetMask'] = cidr2mask($static_ip[1]);
-    $dhcpdata['StaticRouters'] = $static_routers[1];
-    $dhcpdata['StaticDNS'] = $static_dns[1];
+    $dhcpdata['Metric'] = $metric[1] ?? null;
+    $dhcpdata['StaticIP'] = isset($static_ip[1]) && strpos($static_ip[1], '/') !== false
+        ? substr($static_ip[1], 0, strpos($static_ip[1], '/'))
+        : ($static_ip[1] ?? '');
+    $dhcpdata['SubnetMask'] = cidr2mask($static_ip[1] ?? '');
+    $dhcpdata['StaticRouters'] = $static_routers[1] ?? null;
+    $dhcpdata['StaticDNS'] = $static_dns[1] ?? null;
     $dhcpdata['FallbackEnabled'] = empty($fallback) ? false: true;
     $dhcpdata['DefaultRoute'] = $gateway[0] == "gateway";
-    $dhcpdata['NoHookWPASupplicant'] = $nohook_wpa_supplicant[0] == "nohook wpa_supplicant";
+    $dhcpdata['NoHookWPASupplicant'] = ($nohook_wpa_supplicant[0] ?? '') == "nohook wpa_supplicant";
     echo json_encode($dhcpdata);
 }
diff --git a/includes/dhcp.php b/includes/dhcp.php
index 4f89c13e..47b8edfa 100755
--- a/includes/dhcp.php
+++ b/includes/dhcp.php
@@ -52,8 +52,8 @@ function DisplayDHCPConfig()
     $conf = ParseConfig($return);
     exec('cat '. RASPI_DNSMASQ_PREFIX.$ap_iface.'.conf', $return);
     $conf = array_merge(ParseConfig($return));
-    $hosts = (array)$conf['dhcp-host'];
-    $upstreamServers = (array)$conf['server'];
+    $hosts = (array)($conf['dhcp-host'] ?? []);
+    $upstreamServers = (array)($conf['server'] ?? []);
     exec("ip -o link show | awk -F': ' '{print $2}'", $interfaces);
     exec('cat ' . RASPI_DNSMASQ_LEASES, $leases);
 
@@ -280,10 +280,10 @@ function updateDnsmasqConfig($iface,$status)
     $config .='log-facility='.RASPI_DHCPCD_LOG.PHP_EOL;
     $config .='conf-dir=/etc/dnsmasq.d'.PHP_EOL;
     // handle log option
-    if ($_POST['log-dhcp'] == "1") {
+    if (($_POST['log-dhcp'] ?? '') == "1") {
         $config .= "log-dhcp".PHP_EOL;
     }
-    if ($_POST['log-queries'] == "1") {
+    if (($_POST['log-queries'] ?? '') == "1") {
       $config .= "log-queries".PHP_EOL;
     }
     $config .= PHP_EOL;
@@ -317,12 +317,12 @@ function updateDHCPConfig($iface,$status)
     if ($_POST['Metric'] !== '') {
         $cfg[] = 'metric '.$_POST['Metric'];
     }
-    if ($_POST['Fallback'] == 1) {
+    if (($_POST['Fallback'] ?? 0) == 1) {
         $cfg[] = 'profile static_'.$iface;
         $cfg[] = 'fallback static_'.$iface;
     }
-    $cfg[] = $_POST['DefaultRoute'] == '1' ? 'gateway' : 'nogateway';
-    if (( substr($iface, 0, 2) === "wl") && $_POST['NoHookWPASupplicant'] == '1') {
+    $cfg[] = ($_POST['DefaultRoute'] ?? '') == '1' ? 'gateway' : 'nogateway';
+    if (substr($iface, 0, 2) === "wl" && ($_POST['NoHookWPASupplicant'] ?? '') == '1') {
         $cfg[] = 'nohook wpa_supplicant';
     }
     $dhcp_cfg = file_get_contents(RASPI_DHCPCD_CONFIG);
diff --git a/includes/functions.php b/includes/functions.php
index b50bafb4..3099defc 100755
--- a/includes/functions.php
+++ b/includes/functions.php
@@ -54,7 +54,7 @@ function cidr2mask($cidr)
 {
     $ipParts = explode('/', $cidr);
     $ip = $ipParts[0];
-    $prefixLength = $ipParts[1];
+    $prefixLength = $ipParts[1] ?? null;
 
     $ipLong = ip2long($ip);
     $netmaskLong = bindec(str_pad(str_repeat('1', $prefixLength), 32, '0'));
@@ -338,9 +338,9 @@ function CSRFValidate()
 {
     if(isset($_POST['csrf_token'])) {
         $post_token   = $_POST['csrf_token'];
-        $header_token = $_SERVER['HTTP_X_CSRF_TOKEN'];
+        $header_token = $_SERVER['HTTP_X_CSRF_TOKEN'] ?? null;
 
-        if (empty($post_token) && empty($header_token)) {
+        if (empty($post_token) && is_null($header_token)) {
             return false;
         }
         $request_token = $post_token;
@@ -458,6 +458,9 @@ function ParseConfig($arrConfig, $wg = false)
 
         if (strpos($line, "=") !== false) {
             list($option, $value) = array_map("trim", explode("=", $line, 2));
+        } else {
+            $option = $line;
+            $value = "";
         }
         if (empty($config[$option])) {
             $config[$option] = $value ?: true;
diff --git a/templates/dhcp/advanced.php b/templates/dhcp/advanced.php
index 28256114..59db1be9 100644
--- a/templates/dhcp/advanced.php
+++ b/templates/dhcp/advanced.php
@@ -7,7 +7,7 @@
       <div class="input-group">
         <input type="hidden" name="no-resolv" value="0">
         <div class="form-check form-switch">
-          <input class="form-check-input" id="no-resolv" type="checkbox" name="no-resolv" value="1" <?php echo $conf['no-resolv'] ? ' checked="checked"' : "" ?> aria-describedby="no-resolv-description">
+          <input class="form-check-input" id="no-resolv" type="checkbox" name="no-resolv" value="1" <?php echo ($conf['no-resolv'] ?? false) ? ' checked="checked"' : '' ?> aria-describedby="no-resolv-description">
           <label class="form-check-label" for="no-resolv"><?php echo _("Only ever query DNS servers configured below") ?></label>
         </div>
         <p id="no-resolv-description">
@@ -19,9 +19,8 @@
       <div class="js-dhcp-upstream-servers">
         <?php foreach ($upstreamServers as $server): ?>
           <div class="mb-3 input-group input-group-sm js-dhcp-upstream-server">
-            <input type="text" class="form-control" name="server[]" value="<?php echo $server ?>">
+            <input type="text" class="form-control" name="server[]" value="<?php echo $server; ?>">
             <div class="input-group-text js-remove-dhcp-upstream-server"><i class="fas fa-minus"></i></div>
-            </div>
           </div>
         <?php endforeach ?>
       </div>
diff --git a/templates/dhcp/general.php b/templates/dhcp/general.php
index 6eaea7cf..b788c87a 100644
--- a/templates/dhcp/general.php
+++ b/templates/dhcp/general.php
@@ -3,7 +3,7 @@
   <div class="row">
     <div class="mb-3 col-md-6">
       <label for="code">Interface</label>
-        <?php SelectorOptions('interface', $interfaces, $ap_iface, 'cbxdhcpiface', 'loadInterfaceDHCPSelect', $DHCPDisabled); ?>
+        <?php SelectorOptions('interface', $interfaces, $ap_iface, 'cbxdhcpiface', 'loadInterfaceDHCPSelect'); ?>
     </div>
   </div>
 
diff --git a/templates/dhcp/logging.php b/templates/dhcp/logging.php
index a82954a5..975b64a3 100644
--- a/templates/dhcp/logging.php
+++ b/templates/dhcp/logging.php
@@ -4,11 +4,11 @@
   <p><?php echo _("Enable these options to log <code>dhcpcd</code> and <code>dnsmasq</code> activity.") ?></p>
 
   <div class="form-check form-switch">
-    <input class="form-check-input" id="log-dhcp" type="checkbox" name="log-dhcp" value="1" <?php echo $conf['log-dhcp'] ? ' checked="checked"' : "" ?> aria-describedby="log-dhcp-requests">
+    <input class="form-check-input" id="log-dhcp" type="checkbox" name="log-dhcp" value="1" <?php echo !empty($conf['log-dhcp']) ? ' checked="checked"' : "" ?> aria-describedby="log-dhcp-requests">
     <label class="form-check-label" for="log-dhcp"><?php echo _("Log DHCP requests") ?></label>
   </div>
   <div class="form-check form-switch">
-    <input class="form-check-input" id="log-queries" type="checkbox" name="log-queries" value="1" <?php echo $conf['log-queries'] ? ' checked="checked"' : "" ?> aria-describedby="log-dhcp-queries">
+    <input class="form-check-input" id="log-queries" type="checkbox" name="log-queries" value="1" <?php echo !empty($conf['log-queries']) ? ' checked="checked"' : "" ?> aria-describedby="log-dhcp-queries">
     <label class="form-check-label align-middle" for="log-queries"><?php echo _("Log DNS queries") ?></label>
     <input type="button" class="btn btn-outline btn-warning btn-sm align-top ms-4" id="js-cleardnsmasq-log" value="<?php echo _("Clear log"); ?>" />
   </div>
@@ -16,7 +16,7 @@
   <div class="row">
     <div class="mb-3 col-md-8 mt-2">
       <?php
-      if ($conf['log-dhcp'] == 1 || $conf['log-queries'] == 1) {
+      if (($conf['log-dhcp'] ?? 0) == 1 || ($conf['log-queries'] ?? 0) == 1) {
           echo '<textarea class="logoutput text-secondary" id="dnsmasq-log">'.htmlspecialchars($logdata, ENT_QUOTES).'</textarea>';
       } else {
           echo '<textarea class="logoutput my-3"></textarea>';
diff --git a/templates/dhcp/static_leases.php b/templates/dhcp/static_leases.php
index caddc6bb..e92772ae 100644
--- a/templates/dhcp/static_leases.php
+++ b/templates/dhcp/static_leases.php
@@ -47,7 +47,7 @@
         <div class="input-group">
           <input type="hidden" name="dhcp-ignore" value="0">
             <div class="form-check form-switch">
-              <input class="form-check-input" id="dhcp-ignore" type="checkbox" name="dhcp-ignore" value="1" <?php echo $conf['dhcp-ignore'] ? ' checked="checked"' : "" ?> aria-describedby="dhcp-ignore-description">
+              <input class="form-check-input" id="dhcp-ignore" type="checkbox" name="dhcp-ignore" value="1" <?php echo !empty($conf['dhcp-ignore']) ? ' checked="checked"' : "" ?> aria-describedby="dhcp-ignore-description">
               <label class="form-check-label" for="dhcp-ignore"><?php echo _("Limit network access to static clients") ?></label>
             </div>
             <p id="dhcp-ignore-description">