Postfix users,
I am attempting to set up postfix such that using filesystem quotas on
users' mail spaces (a directory whose subdirectories are maildirs).
After RTF{manual, google, list archives}, I haven't been able to find
any good way to do this.
A problematic requirement is that we can't let the user go over their
soft quota, because if they do and their grace runs out, they will be
unable to free up space via IMAP, since common IMAP clients try to copy
messages to Trash as part of the deletion process.
I've thought through the following possibilities, with the given
problems:
1-mailbox_size_limit: ineffective; I'm using maildir, and that's not
filesystem-based anyway.
1-A milter/access policy which checks per recipient to make sure this
message will not put them over quota: fail, we don't know the size of
the message at the point in the SMTP exchange where we can reject
individual users.
2-Same as (1) but assume that the message is message_size_limit large:
annoying because it essentially makes an amount of the users's space
unusable
2-A milter/access policy which checks after end of data to make sure
this message won't put users over quota: fails because this would mean
rejecting the message for all local recipients just because one was over
quota.
3-Just setting quotas and letting procmail fail to deliver the message
and generate a bounce message: fails because postfix keeps trying to
deliver the message for a long time; we would like a relatively quick
fail and notification.
4-Another item in our mailbox_command pipeline which checks the users'
quota and rejects if the message would put them over it: kind of works,
but there is no return code for the command to use to tell procmail that
the delivery failed due to quota issues, causing a proper DSN 5.2.2 to
be returned. Also, the bounce message this generates is a type of
backscatter, though it may be unavoidable because of how the SMTP
protocol works (recipients before message size).
(4) seems to me to be the most promising, if there were a way to have my
quota-checking script tell Postfix to send a 5.2.2 DSN.
Has anybody else dealt with this and prevailed?
Thanks much,
--
Noah Sheppard
Assistant Computer Resource Manager
Taylor University CSE Department
nshep...@cse.taylor.edu
