NetBSD/gnu/dist/postfix/TODO

one queue per rcpt hurts when delivering to agents that don't
get stuck on shell commands or mailbox locks

xxx: bounced as yyy (bounced mail); xxx forwarded as zzz (mail
expanded via :include:).

postconf -f filename

get rid of the relocated feature - perhaps better to bounce recipients
at the SMTP port.

make sendmail/smtpd/cleanup output directory/fifo configurable

if postdrop scrutinizes input, skip the overhead in the pickup
daemon.

add a threshold to sendmail etc. stderr logging, so that class
"info" messages don't go to stderr.

implement an UCE control to accept mail if the sender domain sender
lists us as MX host (rafal wiosna). By the same token, implement
a control to accept mail when the client hostname/parent domain
lists us as their MX host.

received: headers should be generated by the cleanup daemon, and
client attributes ("with", "from", etc.) should be passed along
with the message. This guarantees that forwarded/aliased mail gets
stamped with the queue ID.

toss double-bounce mail even when mail for the local machine is
redirected to another box. See mail_addr_double_bounce().

remote showq access (cookie in maildrop or print some text to inform
the user)

defer: explain mail was bounced after N days

multiple rewrite processes?

gethostbyaddr() uses native name services, which can be slow.

can we detect a client that ignores error responses?

way to block inbound mail based on recipient suffix?

can Postfix implement one switchboard instead of having all these
little lookup tables?

make canonical/virtual/etc. table lookup order configurable

pass on client etc/ attributes along with message to delivery agent

scrutinize file opens in delivery agents just like in qmgr (better:
open the file and see if someone compromised the vmailer account
and is racing against us).

suspend/resume signals + master status (suspended/running) in PID
file.  Maybe use FIFO instead. But, that means requests do not
arrive when the master is stuck.

postedit queue-id command...

more flexible mail queue list command

multiple queues may make ETRN processing less painful because there
is less delayed mail to plow through.

qmgr: configurable incoming/deferred mixing ratio so we can prioritize
new mail over old mail

Replace [my.own.ip.addr] by domain name so that delivered-to has
the desired effect.

Received: header and bounce text will be configurable with ${name}
macros. This requires that everything must cope with newlines in
config parameters (including the SMTP greeting bannner, yuck).

Pass along the client hostname/posting user with queue files, to
be logged by the queue manager.

showq: don't use mail_open_ok() - it assumes coordinated queue
access.

trivial-rewrite: optionally, use DNS to fully qualify hostnames.

pickup/cleanup/qmgr/local: add options record to control internal
features such as canonical/virtual mapping, VERPs etcetera.

Add hook for (domain, user database) support. This is needed if
you have lots of real domains and can't afford a separate master.cf
delivery agent entry for each domain.

Add support for DBZ databases, using the code from INN. Reportedly,
GDB handles large numbers of keys poorly.

Change the front-end to cleanup protocol so that the front-end
sends the expected message size, and so that the cleanup service
can report if there is enough space. This is useful only for the
SMTP server, because pickup can't produce bounce requests: the
bounce service can't read the maildrop file.

On systems with functional UNIX-domain sockets, use that instead
of FIFOs to trigger the pickup and qmgr services. This allows for
some coupling between front-end programs and queue manager, so that
a burst of inbound mail does not lock out the queue manager from
accessing the queue, causing outbound delivery to stop.

There is a need to run `master' services outside the "master"
environment, either for testing (new config files) or for production.
For consistency reasons, programs file names should be taken from
the master.cf file.

    - The showq service. Used by the super user when the mail system
    is down.

    - The smtpd service for "sendmail -bs" emulation. Used by some
    mail posting agents. Output to the maildrop, so that messages
    can be posted even when the mail system is down.

    - The rewrite engine for "sendmail -bt" emulation, for off-line
    testing of configuration files. Requires a method to override
    the location of the rewriting rules file. Or, perhaps there
    should be an official place (/etc/vmailer/testbed?) for playing
    with config files.

postfix-script: detect and/or build missing alias database. In
order to do this we must extract the alias_maps parameter from the
main.cf file, and create any missing files with the right ownerships.

implement the return-receipt-to notification service.

bounce/defer: provide attribute-value interface, for better logging
(expanded-from etc.) and non-delivery reports.

Maintain per-client short-term host status, so we can slow down
unreasonable clients

Make archiving delivered mail a REAL option (queue manager).  What
about one archive per day. The magic could be put into the mail
queue name routines. Just make it aware of the date.

Will the mail system be faster when we avoid moving new messages
incoming->active? How would one detect the arrival of new files?

pickup: pass file descriptor to cleanup instead of copying data.
This violates the principle that all front-end programs protect
the mail system against unreasonably-long inputs.

True ETRN means kick the host out of the queue manager's "dead
hosts" table & move mail from the "hold" queue for that site to
the incoming queue.

postfix-script: make sure that each queue file matches its file id
or we might lose mail.

postfix-script: do database fixups as the unprivileged user

Maintain a pool of pre-allocated queue files, to eliminate file
creation and deletion overhead.