dovecot - Apr 2014 - imap / IPv6 problems?

Hi, I have this intermittant problem.

When sending an email it *sometimes* takes ages before the process
finishes. The  process seems to hang in moving the message to the sent
items" folder". When I disable the IPv6 stack in the network config
(this is MS Windows 7), the hanging process immedialetely completes!
This makens me think that is has to do with the IP stacks. Another
observed effect is a long "rotating wheel" when just klicking on an
imap
folder before the listing in the right pane updates. Here the same trick
solves the problem.

I use Thunderbird on W7 as client and have my mail (3 accounts) on a
remote mailserver. I have full control over that server which can become
handy... Th emailserver is Ubuntu 12.04 LTS with postfix and Dovecot
(2.0.19) from the standard repo's. My IPv6 connections is a native IPv6
from my ISP (xs4all.nl). I have no reason to think that the IPv 6
connecition itself is the problem.

Any advise to investigate this problem is welcome.

Egbert Jan, NL

On 4/4/2014 12:07 ??, Egbert wrote:
> When sending an email it*sometimes*  takes ages before the process
> finishes. The  process seems to hang in moving the message to the sent
> items" folder". When I disable the IPv6 stack in the network
config
> (this is MS Windows 7), the hanging process immedialetely completes!
> This makens me think that is has to do with the IP stacks. Another
> observed effect is a long "rotating wheel" when just klicking on
an imap
> folder before the listing in the right pane updates. Here the same trick
> solves the problem.
Something must be incomplete in your local IPv6 configuration. Have you 
configured IPv6 DNS servers? Are they working?

Troubleshoot your IPv6 network connectivity (check configuration, 
firewalls, etc.). The behaviour you are describing is typical on systems 
which are struggling to use the IPv6 protocol (because it has higher 
priority) and they cannot due to some problem; when IPv6 connectivity 
attempts timeout, IPv4 is used.

We are using Dovecot for years with IPv6 with various clients and we 
have no problems at all.

Nick