---
name: "postdrop"
section: "1"
platform: "macos"
package: "postfix"
version: "1636"
release: "macOS 26.5"
platforms: ["linux", "macos"]
url: "https://new.carta.tech/postdrop"
---

# postdrop(1)

Postfix mail posting utility

## NAME

postdrop - Postfix mail posting utility

## SYNOPSIS

```
postdrop [-rv] [-c config_dir]
```

## DESCRIPTION

The [**postdrop**(1)](/postdrop/1.md) command creates a file in the **maildrop** directory and copies its standard input to the file.

Options:

- **-c** *config\_dir*

  The **main.cf** configuration file is in the named directory instead of the default configuration directory. See also the MAIL\_CONFIG environment setting below.

- **-r**

  Use a Postfix-internal protocol for reading the message from standard input, and for reporting status information on standard output. This is currently the only supported method.

- **-v**

  Enable verbose logging for debugging purposes. Multiple **-v** options make the software increasingly verbose. As of Postfix 2.3, this option is available for the super-user only.

## SECURITY

```

```

The command is designed to run with set-group ID privileges, so that it can write to the **maildrop** queue directory and so that it can connect to Postfix daemon processes.

## DIAGNOSTICS

Fatal errors: malformed input, I/O error, out of memory. Problems are logged to [**syslogd**(8)](/syslogd/8.md) and to the standard error stream. When the input is incomplete, or when the process receives a HUP, INT, QUIT or TERM signal, the queue file is deleted.

## ENVIRONMENT

```

```

- MAIL\_CONFIG

  Directory with the **main.cf** file. In order to avoid exploitation of set-group ID privileges, a non-standard directory is allowed only if:

  - •

    The name is listed in the standard **main.cf** file with the **alternate\_config\_directories** configuration parameter.

  - •

    The command is invoked by the super-user.

## CONFIGURATION PARAMETERS

```

```

The following **main.cf** parameters are especially relevant to this program. The text below provides only a parameter summary. See [**postconf**(5)](/postconf/5.md) for more details including examples.

- **alternate\_config\_directories (empty)**

  A list of non-default Postfix configuration directories that may be specified with "-c config\_directory" on the command line, or via the MAIL\_CONFIG environment parameter.

- **config\_directory (see 'postconf -d' output)**

  The default location of the Postfix main.cf and master.cf configuration files.

- **import\_environment (see 'postconf -d' output)**

  The list of environment parameters that a Postfix process will import from a non-Postfix parent 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".

- **trigger\_timeout (10s)**

  The time limit for sending a trigger to a Postfix daemon (for example, the [**pickup**(8)](/pickup/8.md) or [**qmgr**(8)](/qmgr/8.md) daemon).

Available in Postfix version 2.2 and later:

- **authorized\_submit\_users (static:anyone)**

  List of users who are authorized to submit mail with the [**sendmail**(1)](/sendmail/1.md) command (and with the privileged [**postdrop**(1)](/postdrop/1.md) helper command).

## FILES

```
/var/spool/postfix/maildrop, maildrop queue
```

## SEE ALSO

```
sendmail(1), compatibility interface
postconf(5), configuration parameters
syslogd(8), system logging
```

## LICENSE

```

```

The Secure Mailer license must be distributed with this software.

## AUTHOR(S)

```
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
```