diff --git a/tools/serve/serve.py b/tools/serve/serve.py
index 3086a231402403..56c6f926f8cbbd 100644
--- a/tools/serve/serve.py
+++ b/tools/serve/serve.py
@@ -16,7 +16,6 @@
 from six.moves import urllib
 import uuid
 from collections import defaultdict, OrderedDict
-from itertools import chain, product
 from multiprocessing import Process, Event
 
 from localpaths import repo_root
@@ -702,9 +701,6 @@ def build_config(override_path=None, **kwargs):
 
     return rv
 
-def _make_subdomains_product(s, depth=3):
-    return set(u".".join(x) for x in chain(*(product(s, repeat=i) for i in range(1, depth+1))))
-
 _subdomains = {u"www",
                u"www1",
                u"www2",
@@ -713,10 +709,6 @@ def _make_subdomains_product(s, depth=3):
 
 _not_subdomains = {u"nonexistent"}
 
-_subdomains = _make_subdomains_product(_subdomains)
-
-_not_subdomains = _make_subdomains_product(_not_subdomains)
-
 
 class ConfigBuilder(config.ConfigBuilder):
     """serve config