# man > defer(8postfix)

---
type: CommandReference
command: bounce
mode: man
section: 8
source: man-pages
---

## Quick Reference
- Set postmaster notification address: `bounce_notice_recipient = postmaster`
- Limit bounce message size: `bounce_size_limit = 50000`
- Enable threaded (In-Reply-To) bounces (Postfix ≥ 3.6): `enable_threaded_bounces = yes`
- Specify a custom bounce template file: `bounce_template_file = /etc/postfix/bounce.template`
- Check bounce-related configuration: `postconf | grep bounce`
- View a per-message bounce log: `postcat -bh queue_id`
- Apply configuration changes: `postfix reload`
- Delete a stuck bounce message from the queue: `postsuper -d queue_id`

## Name
`bounce` — Postfix delivery status reports

## Synopsis
**bounce** [generic Postfix daemon options]

## Description
The `bounce` daemon maintains per-message log files with delivery status information. Each log file is named after the queue file that it corresponds to, and is kept in a queue subdirectory named after the service name in **master.cf** (`bounce`, `defer`, or `trace`). It is normally started from the [**master**(8)](http://localhost/phpMan.php/man/master/8/markdown) process manager.

The daemon processes two types of service requests:
- Append a recipient (non-)delivery status record to a per-message log file.
- Enqueue a delivery status notification message, attaching the log file and the original message. On success, the log file is deleted.

Bounce, defer, and trace clients may request log file deletion on failure, enabling clients that cannot retry independently.

## Options
The `bounce` daemon accepts standard Postfix daemon command-line options (see [**master**(5)](http://localhost/phpMan.php/man/master/5/markdown)). The behavior is primarily controlled through **main.cf** configuration parameters. Key parameters are:

### Notification Recipients
- `bounce_notice_recipient` — recipient of postmaster notifications for undelivered mail headers and SMTP transcripts.
- `2bounce_notice_recipient` — recipient of undeliverable mail that cannot be returned to the sender.
- `delay_notice_recipient` — recipient of warnings about mail delayed beyond `$delay_warning_time`.

### Bounce Message Content
- `bounce_size_limit` — maximum amount of original message text included in a non-delivery notification (default: 50000 bytes).
- `bounce_template_file` — path to a configuration file with custom bounce message templates (see [**bounce**(5)](http://localhost/phpMan.php/man/bounce/5/markdown)).
- `enable_threaded_bounces` (Postfix ≥ 3.6) — add `References:` and `In-Reply-To:` headers to bounce messages, linking to the original `Message-ID`.

### Filter and Character Set
- `internal_mail_filter_classes` — categories of Postfix-generated mail subject to before-queue content inspection.
- `smtputf8_autodetect_classes` (Postfix ≥ 3.0) — mail origin classes for which SMTPUTF8 support is autodetected.

### Logging and Identification
- `syslog_facility` — syslog facility (default: `mail`).
- `syslog_name` — prefix prepended to the process name in syslog records.
- `mail_name` — system name shown in headers and bounce messages.
- `process_name`, `process_id`, `service_name` (read-only) — identifiers available in the process environment.

### Performance and Timeouts
- `daemon_timeout` — maximum time a daemon process may handle a request.
- `max_idle` — idle time before shutting down an unused daemon process.
- `max_use` — maximum number of connections served before process termination.
- `ipc_timeout` — timeout for internal communication.
- `deliver_lock_attempts` / `deliver_lock_delay` — retry behavior for acquiring locks on mailbox files or bounce logfiles.

### Queue Directories
- `queue_directory` — top-level Postfix queue directory. Subdirectories `bounce/`, `defer/`, `trace/` hold per-message status log files.

## Examples
**View the bounce log for a queued message:**
shell
postcat -bh 3B2C9F28A4
**Adjust the bounce notification recipient and apply the change:**
shell
postconf -e "bounce_notice_recipient = alias@example.com"
postfix reload
**Limit the size of bounced message content to avoid large DSNs:**
shell
postconf -e "bounce_size_limit = 10000"
postfix reload
**Enable threaded bounces for better MUA threading (Postfix ≥ 3.6):**
shell
postconf -e "enable_threaded_bounces = yes"
postfix reload
**Check all parameters related to bounces:**
shell
postconf | grep bounce
## See Also
[**bounce**(5)](http://localhost/phpMan.php/man/bounce/5/markdown) — bounce message template format  
[**qmgr**(8)](http://localhost/phpMan.php/man/qmgr/8/markdown) — queue manager  
[**postconf**(5)](http://localhost/phpMan.php/man/postconf/5/markdown) — configuration parameters  
[**master**(5)](http://localhost/phpMan.php/man/master/5/markdown) — generic daemon options  
[**master**(8)](http://localhost/phpMan.php/man/master/8/markdown) — process manager  
[**postlogd**(8)](http://localhost/phpMan.php/man/postlogd/8/markdown) — Postfix logging  
[**syslogd**(8)](http://localhost/phpMan.php/man/syslogd/8/markdown) — system logging