--- connection.py	Fri Oct 14 21:46:52 2011
+++ connection1.py	Tue Feb 28 15:42:02 2012
@@ -94,6 +94,13 @@
     else:
         raise ValueError('unrecognized family')
 
+def validate_family(family):
+    '''
+    Checks if the family is valid for the current environment.
+    '''
+    if sys.platform != 'win32' and family == 'AF_PIPE':
+        raise ValueError('Family %s is not recognized.' % family)
+    
 
 def address_type(address):
     '''
@@ -126,6 +133,7 @@
                  or default_family
         address = address or arbitrary_address(family)
 
+        validate_family(family)
         if family == 'AF_PIPE':
             self._listener = PipeListener(address, backlog)
         else:
@@ -163,6 +171,7 @@
     Returns a connection to the address of a `Listener`
     '''
     family = family or address_type(address)
+    validate_family(family)
     if family == 'AF_PIPE':
         c = PipeClient(address)
     else: