diff --git a/jupyter_server/serverapp.py b/jupyter_server/serverapp.py
index 1c70dd60a..91ffbcbae 100644
--- a/jupyter_server/serverapp.py
+++ b/jupyter_server/serverapp.py
@@ -2377,7 +2377,13 @@ def local_url(self) -> str:
         parts = self._get_urlparts(include_token=True)
         # Update with custom pieces.
         if not self.sock:
-            localhost = "[::1]" if ":" in self.ip else "127.0.0.1"
+            localhost = (
+                "[::1]"
+                if ":" in self.ip
+                else self.ip
+                if self.ip.startswith("127.")
+                else "127.0.0.1"
+            )
             parts = parts._replace(netloc=f"{localhost}:{self.port}")
         return parts.geturl()