DISCARD(8)

📦
version 3.11.7 · 3 versions
, in alpine 3.24, arch rolling, nixos 26.05, nixpkgs unstable, ubuntu stonking

💅 DISCARD(8) — bestie edition, from the System Manager's Manual ✨

okay so you opened the manual for discard(8)?? iconic. sit down, grab a strawberry 🍓, we're doing this together.

🌸 NAME 🌸

discard — the Postfix discard mail delivery agent. yes bestie, it's literally an MTA that ✨pretends✨. main character energy fr.

🎀 SYNOPSIS 🎀

discard [generic Postfix daemon options]

🦋 DESCRIPTION 🦋

The Postfix discard(8) delivery agent handles delivery requests that come in from the queue manager. every single request hands it a queue file, a sender address, a next-hop destination — and plot twist — that next-hop destination is the reason for discarding the mail — plus recipient info. 🙈 and listen, that reason can be prefixed with an RFC 3463-compatible detail code, iykyk.

this program expects to be run from the master(8) process manager. it does not run itself, it's not that kinda girl.

so what does it actually do?? it pretends to deliver all recipients in the delivery request, logs the "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. slay 🫶

delivery status reports get sent to the trace(8) daemon as appropriate.

🔒 SECURITY 🔒

ngl the discard(8) mailer is not security-sensitive. it does not talk to the network, and it can be run chrooted at fixed low privilege. lowkey the chillest daemon in the whole ecosystem 💜

📜 STANDARDS 📜

RFC 3463 (Enhanced Status Codes)

🩺 DIAGNOSTICS 🩺

Problems and transactions are logged to syslogd(8) or postlogd(8). so if something's acting up, go read the logs bestie, they're talking.

Depending on the setting of the notify_classes parameter, the postmaster is notified of bounces and of other trouble. 😭

⚙️ CONFIGURATION PARAMETERS ⚙️

Changes to main.cf are picked up automatically as discard(8) processes run for only a limited amount of time. so like, no big dramatic restart needed usually. but if you are impatient: use the command postfix reload to speed up a change. periodt.

the text below provides only a parameter summary. See postconf(5) for more details including examples. (yes, there's more lore, go read it 💅)
  • 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.
  • delay_logging_resolution_limit (2) — The maximal number of digits after the decimal point when logging 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.
  • 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".

✨ 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. no cap, it's required.

🕰️ HISTORY 🕰️

This service was introduced with Postfix version 2.2. so it's been serving looks for a WHILE 💅

👑 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 page bestie 🫶 this one came out of the System Manager's Manual, filed under DISCARD(8), and it ate, fr fr. go forth and discard responsibly 🌈✨

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