diff --git a/mitmproxy/platform/pf.py b/mitmproxy/platform/pf.py
index 97a4c192e..c0397d789 100644
--- a/mitmproxy/platform/pf.py
+++ b/mitmproxy/platform/pf.py
@@ -8,6 +8,7 @@ def lookup(address, port, s):
 
         Returns an (address, port) tuple, or None.
     """
+    s = s.decode()
     spec = "%s:%s" % (address, port)
     for i in s.split("\n"):
         if "ESTABLISHED:ESTABLISHED" in i and spec in i:
diff --git a/tox.ini b/tox.ini
index dc60a442e..db46a8aaa 100644
--- a/tox.ini
+++ b/tox.ini
@@ -7,7 +7,7 @@ deps =
   codecov>=2.0.5
 passenv = CI TRAVIS_BUILD_ID TRAVIS TRAVIS_BRANCH TRAVIS_JOB_NUMBER TRAVIS_PULL_REQUEST TRAVIS_JOB_ID TRAVIS_REPO_SLUG TRAVIS_COMMIT
 setenv =
-    PY3TESTS =  test/netlib test/pathod/ test/mitmproxy/script test/mitmproxy/test_contentview.py test/mitmproxy/test_custom_contentview.py test/mitmproxy/test_app.py test/mitmproxy/test_controller.py test/mitmproxy/test_fuzzing.py test/mitmproxy/test_script.py test/mitmproxy/test_web_app.py test/mitmproxy/test_utils.py test/mitmproxy/test_stateobject.py test/mitmproxy/test_cmdline.py test/mitmproxy/test_contrib_tnetstring.py test/mitmproxy/test_proxy.py test/mitmproxy/test_protocol_http1.py
+    PY3TESTS =  test/netlib test/pathod/ test/mitmproxy/script test/mitmproxy/test_contentview.py test/mitmproxy/test_custom_contentview.py test/mitmproxy/test_app.py test/mitmproxy/test_controller.py test/mitmproxy/test_fuzzing.py test/mitmproxy/test_script.py test/mitmproxy/test_web_app.py test/mitmproxy/test_utils.py test/mitmproxy/test_stateobject.py test/mitmproxy/test_cmdline.py test/mitmproxy/test_contrib_tnetstring.py test/mitmproxy/test_proxy.py test/mitmproxy/test_protocol_http1.py test/mitmproxy/test_platform_pf.py
 
 [testenv:py27]
 commands =