Hi again
Thanks for helping me on this, especially to Steffen. If you do not need case sensitivity on user names the use of a redirect router in exim to lowercase the local part of the address to deliver works well.
If one wants for whatever reasons to have support for user names, that just differ in its case, you could put more logic in that router to make that work. Since I did not need that, I can't post it here...
So the solution to the problem is:
A) Either:
Configure dovecot auth to lower case user names, which LMTP inherits, by setting auth_username_format = "%Lu"
Co-Effect: authenticating logins with wrongly cased user names do also succeed.
B) Or:
Configure your MTA to do the Job. With exim, add a new router just before local delivery takes place, like this:
lowercase_local: debug_print = "R: lower case local_part for local delivery" driver = redirect redirect_router = local_user data = ${lc:${local_part}}
and proceed with the local_user router:
local_user: debug_print = "R: local_user for $local_part@$domain" driver = accept domains = +local_domains check_local_user local_parts = ! root transport = dovecot_lmtp cannot_route_message = Unknown user
then add your LMTP transport:
dovecot_lmtp: driver = lmtp socket = /var/run/dovecot/lmtp batch_max = 256 timeout = 2m delivery_date_add
Has just the effect that login names stay case sensitive (if nothing else is set in dovecot by auth_username_format) but not email addresses, and in spite of being treated as case insensitive, email addresses retain their case.
Maybe some one can add this to the wiki under http://wiki2.dovecot.org/LMTP/Exim?highlight=%28LMTP%29#Using_LMTP_over_UNIX... The code there is anyway not very nice by using the manualroute router with: route_data = whatmeworry # required but not useful
Thanks again to everyone for helping.
Regards, Adrian.
Am 17.12.13 09:38 schrieb Steffen Kaiser:
On Tue, 17 Dec 2013, Steffen Kaiser wrote:
However, it's maybe best to lowercase the local part in the exim lmtp-transport and leave dovecot's LMTP in peace.
that's what I wanted to suggest :)
More or less, it is the duty of the MTA, IMHO.
Um, sorry, forgot the link: http://www.gossamer-threads.com/lists/exim/users/4551
that looks promising.
-- Steffen Kaiser