diff --git a/lib/nntp/tiny/server.py b/lib/nntp/tiny/server.py
index 2c0687c..d910cd5 100644
--- a/lib/nntp/tiny/server.py
+++ b/lib/nntp/tiny/server.py
@@ -70,6 +70,28 @@ class Server():
         thread = threading.Thread(target=spawn)
         thread.start()
 
+    @staticmethod
+    def _is_ipv6(value: str):
+        return value.find(':') >= 0
+
+    @staticmethod
+    def _is_ipv4(value: str):
+        parts = value.split('.')
+
+        if len(parts) > 4 or len(parts) == 0:
+            return False
+
+        for part in parts:
+            if not part.isdecimal():
+                return False
+
+            num = int(part)
+
+            if num > 255:
+                return False
+
+        return True
+
     def run(self):
         if not self.config.has_section('listen'):
             raise ConfigSectionException('listen')
@@ -83,10 +105,13 @@ class Server():
         listeners = list()
 
         for host in hosts:
-            if host.find(':') < 0:
+            if Server._is_ipv6(host):
+                listeners.append(self.listen(host, port, socket.AF_INET6))
+            elif Server._is_ipv4(host):
                 listeners.append(self.listen(host, port, socket.AF_INET))
             else:
-                listeners.append(self.listen(host, port, socket.AF_INET6))
+                for af in (socket.AF_INET, socket.AF_INET6):
+                    listeners.append(self.listen(host, port, af))
 
         if len(listeners) == 0:
             raise ConfigException('No listener hosts specified')