diff --git a/app.py b/app.py
index e76da97..01661c3 100644
--- a/app.py
+++ b/app.py
@@ -203,43 +203,49 @@ def get_real_ip():
     return request.remote_addr
 
 
-import os
-import socket
-import re
-
 def is_allowed_ip(remote_ip, allowed_hosts_str):
-    # awaryjny dostęp
     if os.path.exists("emergency_access.txt"):
         return True
 
     if not allowed_hosts_str or not allowed_hosts_str.strip():
         return False
 
-    allowed_hosts = re.split(r"[\n,]+", allowed_hosts_str.strip())
     allowed_ips = set()
+    hosts = re.split(r"[\n,]+", allowed_hosts_str.strip())
 
-    for host in allowed_hosts:
+    for host in hosts:
         host = host.strip()
         if not host:
             continue
 
-        if re.match(r"^\d{1,3}(\.\d{1,3}){3}$", host):
-            allowed_ips.add(host)
-            continue
-
         try:
-            resolved_ip = socket.gethostbyname(host)
-            allowed_ips.add(resolved_ip)
-        except Exception:
+            ip_obj = ipaddress.ip_address(host)
+            allowed_ips.add(ip_obj)
+            continue
+        except ValueError:
             pass
 
-    try:
-        hostname = socket.gethostbyaddr(remote_ip)[0]
-        app.logger.info(f"Odwiedzający IP: {remote_ip}, host: {hostname}")
-    except Exception:
-        pass
+        try:
+            infos = socket.getaddrinfo(host, None)
+            for family, _, _, _, sockaddr in infos:
+                ip_str = sockaddr[0]
+                try:
+                    ip_obj = ipaddress.ip_address(ip_str)
+                    allowed_ips.add(ip_obj)
+                except ValueError:
+                    continue
+        except Exception as e:
+            app.logger.warning(f"Nie można rozwiązać hosta {host}: {e}")
 
-    return remote_ip in allowed_ips
+    try:
+        remote_ip_obj = ipaddress.ip_address(remote_ip)
+    except ValueError:
+        app.logger.warning(f"Nieprawidłowe IP klienta: {remote_ip}")
+        return False
+
+    is_allowed = remote_ip_obj in allowed_ips
+    app.logger.info(f"is_allowed_ip: {remote_ip_obj} -> {is_allowed} (lista: {allowed_ips})")
+    return is_allowed
 
 
 def to_local(dt):