Index: smtplib.py
===================================================================
--- smtplib.py	(revision 65264)
+++ smtplib.py	(working copy)
@@ -235,27 +235,11 @@
         self.timeout = timeout
         self.esmtp_features = {}
         self.default_port = SMTP_PORT
+        self.local_hostname = local_hostname
         if host:
             (code, msg) = self.connect(host, port)
             if code != 220:
                 raise SMTPConnectError(code, msg)
-        if local_hostname is not None:
-            self.local_hostname = local_hostname
-        else:
-            # RFC 2821 says we should use the fqdn in the EHLO/HELO verb, and
-            # if that can't be calculated, that we should use a domain literal
-            # instead (essentially an encoded IP address like [A.B.C.D]).
-            fqdn = socket.getfqdn()
-            if '.' in fqdn:
-                self.local_hostname = fqdn
-            else:
-                # We can't find an fqdn hostname, so use a domain literal
-                addr = '127.0.0.1'
-                try:
-                    addr = socket.gethostbyname(socket.gethostname())
-                except socket.gaierror:
-                    pass
-                self.local_hostname = '[%s]' % addr
 
     def set_debuglevel(self, debuglevel):
         """Set the debug output level.
@@ -277,7 +261,8 @@
 
         If the hostname ends with a colon (`:') followed by a number, and
         there is no port specified, that suffix will be stripped off and the
-        number interpreted as the port number to use.
+        number interpreted as the port number to use. When using an IPv6 literal
+        address, the port must be passed as a seperate parameter.
 
         Note: This method is automatically invoked by __init__, if a host is
         specified during instantiation.
@@ -295,6 +280,26 @@
         self.sock = self._get_socket(host, port, self.timeout)
         (code, msg) = self.getreply()
         if self.debuglevel > 0: print>>stderr, "connect:", msg
+
+        if self.local_hostname is None:
+            # RFC 2821 says we should use the fqdn in the EHLO/HELO verb, and
+            # if that can't be calculated, that we should use a domain literal
+            # instead (essentially an encoded IP address like [A.B.C.D]) or 
+            # [IPv6:XXXX:XXXX:XXXX:XXXX:XXXX:XXXX:XXXX:XXXX].
+            try:
+                name = socket.getnameinfo(self.sock.getsockname(), 0)
+                if self.sock.family == socket.AF_INET:
+                    self.local_hostname = '[%s]' % name[0]
+                elif self.sock_family == socket.AF_INET6:
+                    self.local_hostname = '[IPv6:%s]' % name[0]
+                else:
+                    if self.debuglevel > 0: print>>stderr, "Unknown address family in SMTP socket"
+            except socket.gaierror, e:
+                if self.debuglevel > 0: print>>stderr, "Error while resolving hostname: ", e.string()
+                pass
+        else:
+            
+
         return (code, msg)
 
     def send(self, str):