diff --git a/cleantalk.antispam/lib/Cleantalk/Common/Helper.php b/cleantalk.antispam/lib/Cleantalk/Common/Helper.php
index f8b64e0..58d9f47 100644
--- a/cleantalk.antispam/lib/Cleantalk/Common/Helper.php
+++ b/cleantalk.antispam/lib/Cleantalk/Common/Helper.php
@@ -373,10 +373,17 @@ static function ip__mask__long_to_number($long_mask)
 	 */
 	static public function ip__validate($ip)
 	{
-		if(!$ip) return false; // NULL || FALSE || '' || so on...
-		if(filter_var($ip, FILTER_VALIDATE_IP, FILTER_FLAG_IPV4) && $ip != '0.0.0.0') return 'v4';  // IPv4
-		if(filter_var($ip, FILTER_VALIDATE_IP, FILTER_FLAG_IPV6) && self::ip__v6_reduce($ip) != '0::0') return 'v6';  // IPv6
-		return false; // Unknown
+		if ( !$ip ) { // NULL || FALSE || '' || so on...
+            return false;
+        }
+        if ( filter_var($ip, FILTER_VALIDATE_IP, FILTER_FLAG_IPV4) && $ip != '0.0.0.0' ) { // IPv4
+            return 'v4';
+        }
+        if ( filter_var($ip, FILTER_VALIDATE_IP, FILTER_FLAG_IPV6) && self::ip__v6_reduce($ip) != '0::0' ) { // IPv6
+            return 'v6';
+        }
+
+        return false; // Unknown
 	}
 
     /**
@@ -428,10 +435,10 @@ static public function ip__v6_normalize($ip)
 	 */
 	static public function ip__v6_reduce($ip)
 	{
-		if(strpos($ip, ':') !== false){
+		if (strpos($ip, ':') !== false){
 			$ip = preg_replace('/:0{1,4}/', ':', $ip);
 			$ip = preg_replace('/:{2,}/', '::', $ip);
-			$ip = strpos($ip, '0') === 0 ? substr($ip, 1) : $ip;
+			$ip = strpos($ip, '0') === 0 && substr($ip, 1) !== false ? substr($ip, 1) : $ip;
 		}
 		return $ip;
 	}
@@ -466,29 +473,74 @@ static public function ip__resolve__cleantalks($ip)
 		if(self::ip__validate($ip)){
 			$url = array_search($ip, self::$cleantalks_servers);
 			return $url
-				? $url
+				? parse_url($url, PHP_URL_HOST)
 				: self::ip__resolve($ip);
 		}else
 			return $ip;
 	}
-	
+
 	/**
-	 * Get URL form IP
-	 *
-	 * @param $ip
-	 *
-	 * @return string
-	 */
-	static public function ip__resolve($ip)
-	{
-		if(self::ip__validate($ip)){
-			$url = gethostbyaddr($ip);
-			if($url)
-				return $url;
-		}
-		return $ip;
-	}
-	
+     * Resolve IP to hostname with FCrDNS (Forward-Confirmed reverse DNS) verification.
+     * Protects against PTR spoofing by verifying the hostname resolves back to the same IP.
+     *
+     * @param string $ip IP address to resolve
+     *
+     * @return string|false Verified hostname or false on failure
+     */
+    public static function ip__resolve($ip)
+    {
+        // Validate IP first
+        $ip_version = self::ip__validate($ip);
+        if (!$ip_version) {
+            return false;
+        }
+
+        // Reverse DNS lookup (PTR record)
+        $hostname = gethostbyaddr($ip);
+
+        // If gethostbyaddr returns the IP itself, it means no PTR record exists
+        if (!$hostname || $hostname === $ip) {
+            return false;
+        }
+
+        // Forward DNS lookup - use dns_get_record() to support both IPv4 (A) and IPv6 (AAAA) records
+        $record_type = ($ip_version === 'v6') ? DNS_AAAA : DNS_A;
+        $ip_field = ($ip_version === 'v6') ? 'ipv6' : 'ip';
+
+        $records = @dns_get_record($hostname, $record_type);
+
+        // If forward lookup fails, we can't verify
+        if (empty($records)) {
+            return false;
+        }
+
+        // Extract IPs from DNS records
+        $forward_ips = array();
+        foreach ($records as $record) {
+            if (isset($record[$ip_field])) {
+                $forward_ips[] = $record[$ip_field];
+            }
+        }
+
+        if (empty($forward_ips)) {
+            return false;
+        }
+
+        // Check if the original IP is in the list of IPs the hostname resolves to
+        if ($ip_version === 'v6') {
+            $normalized_ip = self::ip__v6_normalize($ip);
+            foreach ($forward_ips as $forward_ip) {
+                if (self::ip__v6_normalize($forward_ip) === $normalized_ip) {
+                    return $hostname;
+                }
+            }
+        } elseif (in_array($ip, $forward_ips, true)) {
+            return $hostname;
+        }
+
+        return false;
+    }
+
 	/**
 	 * Resolve DNS to IP
 	 *
diff --git a/cleantalk.antispam/lib/Cleantalk/Common/RemoteCalls.php b/cleantalk.antispam/lib/Cleantalk/Common/RemoteCalls.php
index eaebd58..6fbe301 100644
--- a/cleantalk.antispam/lib/Cleantalk/Common/RemoteCalls.php
+++ b/cleantalk.antispam/lib/Cleantalk/Common/RemoteCalls.php
@@ -3,6 +3,8 @@
 namespace Cleantalk\Common;
 
 use Cleantalk\Common\Variables\Get;
+use Cleantalk\Common\Variables\Request;
+use Cleantalk\Common\Helper;
 
 abstract class RemoteCalls
 {
@@ -30,19 +32,35 @@ public function __construct( $api_key )
         $this->available_rc_actions = $this->getAvailableRcActions();
     }
 
+    /**
+     * @param $name
+     * @return mixed
+     * @psalm-taint-source input
+     */
+    public static function getVariable($name)
+    {
+        return Request::get($name);
+    }
+
     /**
 	 * Checking if the current request is the Remote Call
 	 *
 	 * @return bool
 	 */
-	public static function check()
+    public static function check()
     {
-		return
-			Get::get( 'spbc_remote_call_token' ) &&
-			Get::get( 'spbc_remote_call_action' ) &&
-			Get::get( 'plugin_name' ) &&
-			in_array( Get::get( 'plugin_name' ), array( 'antispam','anti-spam', 'apbct' ) );
-	}
+        if (static::getVariable('spbc_remote_call_action')) {
+            static::getVariable('spbc_remote_call_token')
+            ? self::checkWithToken()
+            : false;
+        }
+        return false;
+    }
+
+    public static function checkWithToken()
+    {
+        return in_array(static::getVariable('plugin_name'), array('antispam', 'anti-spam', 'apbct'));
+    }
 
     /**
      * Execute corresponding method of RemoteCalls if exists