diff --git a/Lib/http/cookiejar.py b/Lib/http/cookiejar.py
index eaa76c26b9c591..3a7b3ad7405154 100644
--- a/Lib/http/cookiejar.py
+++ b/Lib/http/cookiejar.py
@@ -641,7 +641,7 @@ def eff_request_host(request):
 
     """
     erhn = req_host = request_host(request)
-    if req_host.find(".") == -1 and not IPV4_RE.search(req_host):
+    if "." not in req_host:
         erhn = req_host + ".local"
     return req_host, erhn