diff --git a/src/schemas/api.py b/src/schemas/api.py
index 237c4e14..4863d99a 100644
--- a/src/schemas/api.py
+++ b/src/schemas/api.py
@@ -681,10 +681,17 @@ class WebhookEndpointCreate(WebhookEndpointBase):
         if parsed.hostname:
             try:
                 ip_address = ipaddress.ip_address(parsed.hostname)
-                if ip_address.is_private:
-                    raise ValueError("Private IP addresses are not allowed")
-            except ValueError:  # Not an IP address, might be a hostname
-                pass
+            except ValueError:  # Not an IP literal — a hostname, leave it alone
+                ip_address = None
+            if ip_address is not None and (
+                ip_address.is_private
+                or ip_address.is_loopback
+                or ip_address.is_link_local
+                or ip_address.is_reserved
+                or ip_address.is_multicast
+                or ip_address.is_unspecified
+            ):
+                raise ValueError("Private/internal IP addresses are not allowed")
 
         return v