diff --git a/tests/server.py b/tests/server.py
index fbd7e37..e7542dc 100644
--- a/tests/server.py
+++ b/tests/server.py
@@ -208,12 +208,10 @@ class ServerTestCase(AsyncTestCase):
         cls._server = yield from cls.start_server()
 
         sock = cls._server.sockets[0]
-        cls._client_host, _ = yield from cls.loop.getnameinfo(('127.0.0.1', 0))
         cls._server_addr = '127.0.0.1'
         cls._server_port = sock.getsockname()[1]
 
-        host = '[%s]:%d,%s ' % (cls._server_addr, cls._server_port,
-                                cls._client_host)
+        host = '[%s]:%d,localhost ' % (cls._server_addr, cls._server_port)
 
         with open('known_hosts', 'w') as known_hosts:
             known_hosts.write(host)
diff --git a/tests/test_auth_keys.py b/tests/test_auth_keys.py
index 1d625ef..72a49f7 100644
--- a/tests/test_auth_keys.py
+++ b/tests/test_auth_keys.py
@@ -13,13 +13,13 @@
 """Unit tests for matching against authorized_keys file"""
 
 import unittest
-from unittest.mock import patch
 
 import asyncssh
 
-from .util import TempDirTestCase, x509_available
+from .util import TempDirTestCase, patch_getnameinfo, x509_available
 
 
+@patch_getnameinfo
 class _TestAuthorizedKeys(TempDirTestCase):
     """Unit tests for auth_keys module"""
 
@@ -69,36 +69,22 @@ class _TestAuthorizedKeys(TempDirTestCase):
     def match_keys(self, tests, x509=False):
         """Match against authorized keys"""
 
-        def getnameinfo(sockaddr, flags):
-            """Mock reverse DNS lookup of client address"""
-
-            # pylint: disable=unused-argument
-
-            host, port = sockaddr
-
-            if host == '127.0.0.1':
-                return ('localhost', port)
-            else:
-                return sockaddr
-
-        with patch('socket.getnameinfo', getnameinfo):
-            for keys, matches in tests:
-                auth_keys = self.build_keys(keys, x509)
-                for (msg, keynum, client_addr,
-                     cert_principals, match) in matches:
-                    with self.subTest(msg, x509=x509):
-                        if x509:
-                            result, trusted_cert = auth_keys.validate_x509(
-                                self.imported_certlist[keynum], client_addr)
-                            if (trusted_cert and trusted_cert.subject !=
-                                    self.imported_certlist[keynum].subject):
-                                result = None
-                        else:
-                            result = auth_keys.validate(
-                                self.imported_keylist[keynum], client_addr,
-                                cert_principals, keynum == 1)
-
-                        self.assertEqual(result is not None, match)
+        for keys, matches in tests:
+            auth_keys = self.build_keys(keys, x509)
+            for (msg, keynum, client_addr, cert_principals, match) in matches:
+                with self.subTest(msg, x509=x509):
+                    if x509:
+                        result, trusted_cert = auth_keys.validate_x509(
+                            self.imported_certlist[keynum], client_addr)
+                        if (trusted_cert and trusted_cert.subject !=
+                                self.imported_certlist[keynum].subject):
+                            result = None
+                    else:
+                        result = auth_keys.validate(
+                            self.imported_keylist[keynum], client_addr,
+                            cert_principals, keynum == 1)
+
+                    self.assertEqual(result is not None, match)
 
     def test_matches(self):
         """Test authorized keys matching"""
diff --git a/tests/test_connection_auth.py b/tests/test_connection_auth.py
index 3da8a5b..ff3e3cc 100644
--- a/tests/test_connection_auth.py
+++ b/tests/test_connection_auth.py
@@ -23,8 +23,8 @@ from asyncssh.packet import String
 from asyncssh.public_key import CERT_TYPE_USER, CERT_TYPE_HOST
 
 from .server import Server, ServerTestCase
-from .util import asynctest, gss_available, patch_gss, make_certificate
-from .util import x509_available
+from .util import asynctest, gss_available, patch_getnameinfo, patch_gss
+from .util import make_certificate, x509_available
 
 
 class _FailValidateHostSSHServerConnection(asyncssh.SSHServerConnection):
@@ -455,6 +455,7 @@ class _TestGSSFQDN(ServerTestCase):
         yield from conn.wait_closed()
 
 
+@patch_getnameinfo
 class _TestHostBasedAuth(ServerTestCase):
     """Unit tests for host-based authentication"""
 
@@ -579,7 +580,7 @@ class _TestHostBasedAuth(ServerTestCase):
         """Test stripping of trailing dot from client host"""
 
         with (yield from self.connect(username='user', client_host_keys='skey',
-                                      client_host=self._client_host + '.',
+                                      client_host='localhost.',
                                       client_username='user')) as conn:
             pass
 
@@ -667,6 +668,7 @@ class _TestHostBasedAsyncServerAuth(_TestHostBasedAuth):
                                     client_username='user')
 
 
+@patch_getnameinfo
 class _TestLimitedHostBasedSignatureAlgs(ServerTestCase):
     """Unit tests for limited host key signature algorithms"""
 
diff --git a/tests/util.py b/tests/util.py
index 42bb596..4d92ec3 100644
--- a/tests/util.py
+++ b/tests/util.py
@@ -84,6 +84,24 @@ def asynctest35(func):
     return async_wrapper
 
 
+def patch_getnameinfo(cls):
+    """Decorator for patching socket.getnameinfo"""
+
+    def getnameinfo(sockaddr, flags):
+        """Mock reverse DNS lookup of client address"""
+
+        # pylint: disable=unused-argument
+
+        host, port = sockaddr
+
+        if host == '127.0.0.1':
+            return ('localhost', port)
+        else:
+            return sockaddr
+
+    return patch('socket.getnameinfo', getnameinfo)(cls)
+
+
 def patch_gss(cls):
     """Decorator for patching GSSAPI classes"""