diff --git a/scripts/pi-hole/js/customdns.js b/scripts/pi-hole/js/customdns.js
index 73c40ddb..e30c6f4f 100644
--- a/scripts/pi-hole/js/customdns.js
+++ b/scripts/pi-hole/js/customdns.js
@@ -9,7 +9,7 @@ $(document).ready(function() {
         "columnDefs": [ {
             "targets": 2,
             "render": function ( data, type, row ) {
-                return "<button id=\"" + row[0] + "\" class=\"btn btn-danger btn-xs deleteCustomDNS\" type=\"button\">" +
+                return "<button class=\"btn btn-danger btn-xs deleteCustomDNS\" type=\"button\" data-domain='"+row[0]+"' data-ip='"+row[1]+"'>" +
                            "<span class=\"glyphicon glyphicon-trash\"></span>" +
                        "</button>";
             }
@@ -44,11 +44,14 @@ function addCustomDNS()
 
 function deleteCustomDNS()
 {
+    var ip = $(this).attr("data-ip");
+    var domain = $(this).attr("data-domain");
+
     $.ajax({
         url: "scripts/pi-hole/php/customdns.php",
         method: "post",
         dataType: 'json',
-        data: {"action":"delete", "domain": $(this).prop('id')},
+        data: {"action":"delete", "domain": domain, "ip": ip},
         success: function(response) {
             if (response.success)
                 table.ajax.reload();
diff --git a/scripts/pi-hole/php/customdns.php b/scripts/pi-hole/php/customdns.php
index 0633067d..8c0d0bb1 100644
--- a/scripts/pi-hole/php/customdns.php
+++ b/scripts/pi-hole/php/customdns.php
@@ -18,9 +18,8 @@
         $entries = getCustomDNSEntries();
 
         $data = [];
-
-        foreach ($entries as $domain => $ip)
-            $data[] = [ $domain, $ip ];
+        foreach ($entries as $entry)
+            $data[] = [ $entry->domain, $entry->ip ];
 
         return [ "data" => $data ];
     }
@@ -42,7 +41,10 @@
                 if (count($explodedLine) != 2)
                     continue;
 
-                $entries[$explodedLine[1]] = $explodedLine[0];
+                $data = new \stdClass();
+                $data->ip = $explodedLine[0];
+                $data->domain = $explodedLine[1];
+                $entries[] = $data;
             }
 
             fclose($handle);
@@ -61,7 +63,9 @@
             if (empty($ip))
                 return errorJsonResponse("IP must be set");
 
-            if (!filter_var($ip, FILTER_VALIDATE_IP))
+            $ipType = get_ip_type($ip);
+
+            if (!$ipType)
                 return errorJsonResponse("IP must be valid");
 
             if (empty($domain))
@@ -72,8 +76,10 @@
 
             $existingEntries = getCustomDNSEntries();
 
-            if (array_key_exists($domain, $existingEntries))
-                return errorJsonResponse("This domain already has a custom DNS entry");
+            foreach ($existingEntries as $entry)
+                if ($entry->domain == $domain)
+                    if (get_ip_type($entry->ip) == $ipType)
+                        return errorJsonResponse("This domain already has a custom DNS entry for an IPv" . $ipType);
 
             exec("sudo pihole -a addcustomdns ".$ip." ".$domain);
             exec("sudo pihole -a restartdns");
@@ -90,17 +96,29 @@
     {
         try
         {
+            $ip = !empty($_REQUEST['ip']) ? $_REQUEST['ip']: "";
             $domain = !empty($_REQUEST['domain']) ? $_REQUEST['domain']: "";
 
+            if (empty($ip))
+                return errorJsonResponse("IP must be set");
+
             if (empty($domain))
                 return errorJsonResponse("Domain must be set");
 
             $existingEntries = getCustomDNSEntries();
 
-            if (!array_key_exists($domain, $existingEntries))
-                return errorJsonResponse("This domain does not have a custom DNS entry");
+            $found = false;
+            foreach ($existingEntries as $entry)
+                if ($entry->domain == $domain)
+                    if ($entry->ip == $ip) {
+                        $found = true;
+                        break;
+                    }
 
-            exec("sudo pihole -a removecustomdns ".$domain);
+            if (!$found)
+                return errorJsonResponse("This domain/ip association does not exist");
+
+            exec("sudo pihole -a removecustomdns ".$ip." ".$domain);
             exec("sudo pihole -a restartdns");
 
             return successJsonResponse();
diff --git a/scripts/pi-hole/php/func.php b/scripts/pi-hole/php/func.php
index 7c1d3d65..6a6afe7f 100644
--- a/scripts/pi-hole/php/func.php
+++ b/scripts/pi-hole/php/func.php
@@ -13,6 +13,13 @@ function is_valid_domain_name($domain_name)
         preg_match("/^[^\.]{1,63}(\.[^\.]{1,63})*$/", $domain_name)); // Length of each label
 }
 
+function get_ip_type($ip)
+{
+    return  filter_var($ip, FILTER_VALIDATE_IP, FILTER_FLAG_IPV4) ? 4 :
+           (filter_var($ip, FILTER_VALIDATE_IP, FILTER_FLAG_IPV6) ? 6 :
+            0);
+}
+
 function checkfile($filename) {
     if(is_readable($filename))
     {