diff --git a/irctest/basecontrollers.py b/irctest/basecontrollers.py
index 82764d7..aa43f0c 100644
--- a/irctest/basecontrollers.py
+++ b/irctest/basecontrollers.py
@@ -58,16 +58,16 @@ class BaseClientController(_BaseController):
 
 class BaseServerController(_BaseController):
     """Base controller for IRC server."""
+    port_open = False
     def run(self, hostname, port, password,
             valid_metadata_keys, invalid_metadata_keys):
         raise NotImplementedError()
     def registerUser(self, case, username, password=None):
         raise NotImplementedByController('registration')
-    def wait_for_port(self, proc, port):
-        port_open = False
-        while not port_open:
+    def wait_for_port(self):
+        while not self.port_open:
             time.sleep(0.1)
-            for conn in psutil.Process(proc.pid).connections():
-                if conn.laddr[1] == port:
-                    port_open = True
+            for conn in psutil.Process(self.proc.pid).connections():
+                if conn.laddr[1] == self.port:
+                    self.port_open = True
 
diff --git a/irctest/cases.py b/irctest/cases.py
index 0cab66e..273978a 100644
--- a/irctest/cases.py
+++ b/irctest/cases.py
@@ -235,6 +235,7 @@ class BaseServerTestCase(_IrcTestCase):
     def addClient(self, name=None, show_io=None):
         """Connects a client to the server and adds it to the dict.
         If 'name' is not given, uses the lowest unused non-negative integer."""
+        self.controller.wait_for_port()
         if not name:
             name = max(map(int, list(self.clients)+[0]))+1
         show_io = show_io if show_io is not None else self.show_io
diff --git a/irctest/controllers/charybdis.py b/irctest/controllers/charybdis.py
index 3338caf..668df01 100644
--- a/irctest/controllers/charybdis.py
+++ b/irctest/controllers/charybdis.py
@@ -47,6 +47,7 @@ class CharybdisController(BaseServerController, DirectoryBasedController):
                     'Defining valid and invalid METADATA keys.')
         assert self.proc is None
         self.create_config()
+        self.port = port
         password_field = 'password = "{}";'.format(password) if password else ''
         with self.open_file('server.conf') as fd:
             fd.write(TEMPLATE_CONFIG.format(
@@ -60,7 +61,6 @@ class CharybdisController(BaseServerController, DirectoryBasedController):
             ],
             stderr=subprocess.DEVNULL
             )
-        self.wait_for_port(self.proc, port)
 
 
 def get_irctest_controller_class():
diff --git a/irctest/controllers/inspircd.py b/irctest/controllers/inspircd.py
index d2d5ee4..6283803 100644
--- a/irctest/controllers/inspircd.py
+++ b/irctest/controllers/inspircd.py
@@ -5,6 +5,7 @@ import tempfile
 import subprocess
 
 from irctest import authentication
+from irctest.basecontrollers import NotImplementedByController
 from irctest.basecontrollers import BaseServerController, DirectoryBasedController
 
 TEMPLATE_CONFIG = """
@@ -33,6 +34,7 @@ class InspircdController(BaseServerController, DirectoryBasedController):
             raise NotImplementedByController(
                     'Defining valid and invalid METADATA keys.')
         assert self.proc is None
+        self.port = port
         self.create_config()
         password_field = 'password="{}"'.format(password) if password else ''
         with self.open_file('server.conf') as fd:
@@ -45,7 +47,6 @@ class InspircdController(BaseServerController, DirectoryBasedController):
             os.path.join(self.directory, 'server.conf')],
             stdout=subprocess.DEVNULL
             )
-        self.wait_for_port(self.proc, port)
 
 def get_irctest_controller_class():
     return InspircdController
diff --git a/irctest/controllers/mammon.py b/irctest/controllers/mammon.py
index b5d61c4..7a80b8a 100644
--- a/irctest/controllers/mammon.py
+++ b/irctest/controllers/mammon.py
@@ -80,6 +80,7 @@ class MammonController(BaseServerController, DirectoryBasedController):
         if password is not None:
             raise NotImplementedByController('PASS command')
         assert self.proc is None
+        self.port = port
         self.create_config()
         with self.open_file('server.yml') as fd:
             fd.write(TEMPLATE_CONFIG.format(
@@ -93,7 +94,6 @@ class MammonController(BaseServerController, DirectoryBasedController):
         #    print(fd.read())
         self.proc = subprocess.Popen(['mammond', '--nofork', #'--debug',
             '--config', os.path.join(self.directory, 'server.yml')])
-        self.wait_for_port(self.proc, port)
 
     def registerUser(self, case, username, password=None):
         # XXX: Move this somewhere else when