Look, below, please.  [The domain] is rejecting emails.  It acts as if
the email address is case sensitive.  Can you help?

Never noticed this before, but indeed, you are right. It's a probably never-thought-of side-effect of the way the mail server can manage to deliver mail to non-existing addresses.

It works this way: to begin with, only system users can receive mail.
The mail server I am using, courier, can alias an entire domain to a
system user. Thus, I have aliased your entire domain to the user [you]
on the server machine. This would normally cause any mail for your
domain to be delivered to your local mailbox.

From there on, courier has expanded and refined the delivery alternatives
with a simple trick: it takes the username part of the e-mail address
(the part before @domain) and looks for a .courier-[username] file in
the directory of the user to whom the mail is to be delivered. If such
a file is found, the mail is sent to the address(es) in that file. If
such a file is not found, the mail is sent to the address(es) specified
in .courier-default . If .courier-default does not exist, the mail is
rejected with a "user unknown" error.

Now then. The mail server itself doesn't care about case in e-mail
addresses, but the file system cares about case in file names. The
mail server has no idea who INFO5@ might be; actually, it knows damn
well that there is no such user. Before bouncing the mail, it checks
whether a .courier-INFO5 file exists in the directory of the user to
whom the domain is aliased. To check that, the mail server has to ask
the file system. The file system, being case-sensitive, answers "no,
there's no such file". Since no default is defined either, the mail
server knows nothing better than that the mail should indeed be
rejected.

One workaround for this is to create .courier-default and accept
any mail for the domain. With your 900+ spams per day I don't think
that this is a viable option.

Another workaround is to create .courier-[username] files for all
possible case variations of a user name. That's far from practical,
but I created .courier-INFO5 and .courier-Info5 for now and did the
same with the rest of your addresses. Tested, they work. If anyone
insists on mailing iNFo5@ , I think he deserves to get a bounce.

The real solution is to have the mail server search case-insensitively
for the .courier-address files instead of just checking whether they
exist or not. That's a programming change in the internals of the mail
server, which would have to be implemented by the server developer in
a future version and would only be useful to you after I upgrade my
server to that version. I am CC-ing this to the appropriate mailing
list as a suggestion to the developer.

Z




-------------------------------------------------------
This SF.net email is sponsored by: ValueWeb: Dedicated Hosting for just $79/mo with 500 GB of bandwidth! No other company gives more support or power for your dedicated server
http://click.atdmt.com/AFF/go/sdnxxaff00300020aff/direct/01/
_______________________________________________
courier-users mailing list
[EMAIL PROTECTED]
Unsubscribe: https://lists.sourceforge.net/lists/listinfo/courier-users

Reply via email to