diff --git a/Lib/asyncore.py b/Lib/asyncore.py
index db426d71a8b..88845012e48 100644
--- a/Lib/asyncore.py
+++ b/Lib/asyncore.py
@@ -60,10 +60,12 @@ except NameError:
     socket_map = {}
 
 def _strerror(err):
-    res = os.strerror(err)
-    if res == 'Unknown error':
-        res = errorcode[err]
-    return res
+    try:
+        return strerror(err)
+    except (ValueError, OverflowError):
+        if err in errorcode:
+            return errorcode[err]
+        return "Unknown error %s" %err
 
 class ExitNow(Exception):
     pass
@@ -395,7 +397,11 @@ class dispatcher:
     # cheap inheritance, used to pass all other attribute
     # references to the underlying socket object.
     def __getattr__(self, attr):
-        return getattr(self.socket, attr)
+        try:
+            return getattr(self.socket, attr)
+        except AttributeError:
+            raise AttributeError("%s instance has no attribute '%s'"
+                                 %(self.__class__.__name__, attr))
 
     # log and log_info may be overridden to provide more sophisticated
     # logging and warning methods. In general, log is for 'hit' logging
diff --git a/Lib/test/test_asyncore.py b/Lib/test/test_asyncore.py
index ba89f125dbd..4db29ca14ea 100644
--- a/Lib/test/test_asyncore.py
+++ b/Lib/test/test_asyncore.py
@@ -302,6 +302,18 @@ class DispatcherTests(unittest.TestCase):
                     'warning: unhandled accept event']
         self.assertEquals(lines, expected)
 
+    def test_issue_8594(self):
+        d = asyncore.dispatcher(socket.socket())
+        # make sure the error message no longer refers to the socket
+        # object but the dispatcher instance instead
+        try:
+            d.foo
+        except AttributeError as err:
+            self.assertTrue('dispatcher instance' in str(err))
+        else:
+            self.fail("exception not raised")
+        # test cheap inheritance with the underlying socket
+        self.assertEqual(d.family, socket.AF_INET)
 
 
 class dispatcherwithsend_noread(asyncore.dispatcher_with_send):
diff --git a/Misc/NEWS b/Misc/NEWS
index c9a82fdacfd..3256e31c49e 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -40,6 +40,12 @@ Core and Builtins
 Library
 -------
 
+- Issue #8573: asyncore _strerror() function might throw ValueError.
+
+- Issue #8483: asyncore.dispatcher's __getattr__ method produced confusing 
+  error messages when accessing undefined class attributes because of the cheap 
+  inheritance with the underlying socket object.
+
 - Issue #7472: Fixed typo in email.encoders module; messages using ISO-2022
   character sets will now consistently use a Content-Transfer-Encoding of
   7bit rather than sometimes being marked as 8bit.