diff --git a/letsencrypt-postfix/PostfixConfigGenerator.py b/letsencrypt-postfix/PostfixConfigGenerator.py
index 34654a2d1..9863d05d2 100755
--- a/letsencrypt-postfix/PostfixConfigGenerator.py
+++ b/letsencrypt-postfix/PostfixConfigGenerator.py
@@ -171,6 +171,15 @@ class PostfixConfigGenerator:
         """Returns all names that may be authenticated.
         :rtype: `list` of `str`
         """
+        var_names = ('myhostname', 'mydomain', 'myorigin')
+        names_found = set()
+        for num, line in enumerate(self.cf):
+            num, found_var, found_value = parse_line((num, line))
+            if found_var in var_names:
+                names_found.add(found_value)
+        name_list = list(names_found)
+        name_list.sort()
+        return name_list
 
     def deploy_cert(self, domain, _cert_path, key_path, _chain_path, fullchain_path):
         """Deploy certificate.
diff --git a/letsencrypt-postfix/TestPostfixConfigGenerator.py b/letsencrypt-postfix/TestPostfixConfigGenerator.py
index 98a0afb5d..e1d921c6f 100644
--- a/letsencrypt-postfix/TestPostfixConfigGenerator.py
+++ b/letsencrypt-postfix/TestPostfixConfigGenerator.py
@@ -48,7 +48,7 @@ class TestPostfixConfigGenerator(unittest.TestCase):
         pass
 
     def testGetAllNames(self):
-        sorted_names = ('fubard.org', 'mail.fubard.org')
+        sorted_names = ['fubard.org', 'mail.fubard.org']
         postfix_config_gen = pcg.PostfixConfigGenerator(
             self.config,
             self.postfix_dir,