DISCARD(8postfix)

📦 version 3.8.6, in debian bookworm, ubuntu jammy, ubuntu noble

💌 DISCARD(8postfix) — the Postfix discard mail delivery agent

okay bestie, so this is the manual page for discard, aka the Postfix discard mail delivery agent. it lives in section 8 of the Postfix manual (you know, the daemon-y one). it does NOT deliver your mail. it pretends to. and honestly? iconic behaviour. ✨

🌸 NAME 🌸

discard — Postfix discard mail delivery agent

🎀 SYNOPSIS 🎀

discard [generic Postfix daemon options]

💖 DESCRIPTION 💖

so the Postfix discard(8) delivery agent is out here processing delivery requests that come in from the queue manager. every single request hands it a few things:

  • a queue file
  • a sender address
  • a next-hop destination — and bestie, that destination is literally treated as the reason for discarding the mail
  • recipient information

and the reason can have an RFC 3463-compatible detail code prefixed onto it, no cap. this program is expecting to be run from the master(8) process manager, so don't just go running it in your terminal for funsies.

what it actually does: the discard(8) delivery agent pretends to deliver all recipients in the delivery request, logs that "next-hop" destination as the reason for discarding the mail, updates the queue file, and then either marks recipients as finished or tells the queue manager that delivery should be tried again at a later time. it's giving "I'm handling it 💅" while very much not handling it.

delivery status reports get sent to the trace(8) daemon as appropriate. so like, receipts are still being kept. 🧾

🔒 SECURITY 🔒

the discard(8) mailer is not security-sensitive, bestie. it does not talk to the network at all, and it can be run chrooted at fixed low privilege. lowkey the safest little gremlin in the whole Postfix ecosystem. 🦋

📜 STANDARDS 📜

🩺 DIAGNOSTICS 🩺

problems and transactions are logged to syslogd(8) or postlogd(8). so if something goes weird, it's going in the group chat (the log).

depending on the setting of the notify_classes parameter, the postmaster is notified of bounces and of other trouble. the postmaster will be finding out. 🙈

⚙️ CONFIGURATION PARAMETERS ⚙️

changes to main.cf are picked up automatically as discard(8) processes run for only a limited amount of time. and if you're impatient (same), use the command postfix reload to speed up a change.

the text below provides only a parameter summary. see postconf(5) for more details including examples. don't come for me, I'm just the messenger. 💀
  • config_directory (see 'postconf -d' output) — the default location of the Postfix main.cf and master.cf configuration files.
  • daemon_timeout (18000s) — how much time a Postfix daemon process may take to handle a request before it is terminated by a built-in watchdog timer. yes, the watchdog is real and it will pull up.
  • delay_logging_resolution_limit (2) — the maximal number of digits after the decimal point when logging sub-second delay values.
  • double_bounce_sender (double-bounce) — the sender address of postmaster notifications that are generated by the mail system.
  • ipc_timeout (3600s) — the time limit for sending or receiving information over an internal communication channel.
  • max_idle (100s) — the maximum amount of time that an idle Postfix daemon process waits for an incoming connection before terminating voluntarily. it's not ghosting you, it's just on a timer. ✨
  • max_use (100) — the maximal number of incoming connections that a Postfix daemon process will service before terminating voluntarily.
  • process_id (read-only) — the process ID of a Postfix command or daemon process.
  • process_name (read-only) — the process name of a Postfix command or daemon process.
  • queue_directory (see 'postconf -d' output) — the location of the Postfix top-level queue directory.
  • syslog_facility (mail) — the syslog facility of Postfix logging.
  • syslog_name (see 'postconf -d' output) — a prefix that is prepended to the process name in syslog records, so that, for example, "smtpd" becomes "prefix/smtpd". it's giving ✨branding✨.

Available in Postfix 3.3 and later:

  • service_name (read-only) — the master.cf service name of a Postfix daemon process.

👀 SEE ALSO 👀

📄 LICENSE 📄

The Secure Mailer license must be distributed with this software. periodt. 💅

🕰️ HISTORY 🕰️

This service was introduced with Postfix version 2.2. a true elder of the Postfix friend group. 👑

👑 AUTHOR(S) 👑

Victor Duchovni Morgan Stanley

Based on code by:

Wietse Venema IBM T.J. Watson Research P.O. Box 704 Yorktown Heights, NY 10598, USA

Wietse Venema Google, Inc. 111 8th Avenue New York, NY 10011, USA

and that's the whole DISCARD(8postfix) manual page, bestie — Postfix discard mail delivery agent, straight from the Postfix documentation set. go forth and discard responsibly (or, y'know, let the queue manager do it). 🫶💖🎀

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