policyd-rate-limit

Postfix rate limiter SMTP policy daemon

How it works

It depends on the Postfix policy delegation protocol, it searches for the sasl_username and based on the defined limits stored in a MySQl database it rejects or allows action=DUNNO the email to be sent.

How to use

```txt USAGE: policyd-rate-limit [OPTIONS] --dsn [SUBCOMMAND]

FLAGS: -h, --help Prints help information -V, --version Prints version information

OPTIONS: -d, --dsn mysql://:@tcp(:)/ --max mysql pool max connections [default: 50] --min mysql pool min connections [default: 3] -s, --socket path to Unix domain socket [default: /tmp/policy-rate-limit.sock]

SUBCOMMANDS: cuser Create the user if not found, defaults: 100 messages per day help Prints this message or the help of the given subcommand(s) ```

For the subcommand cuser:

```txt Create the user if not found, defaults: 100 messages per day

USAGE: policyd-rate-limit --dsn cuser [OPTIONS]

FLAGS: -h, --help Prints help information -V, --version Prints version information

OPTIONS: -l, --limit maximum allowed messages [default: 100] -r, --rate rate in seconds, limits the messages to be sent in the defined period [default: 86400] ```

Use a supervisor (immortal) to run policyd-rate-limit, for example to create users if not found and to only allow 3 emails every hour use:

policyd-rate-limit -d mysql://root:test@tcp(localhost)/policyd -s /var/run/policy-rate-limit.sock cuser -l 3 -r 3600

The database schema:

``sql CREATE SCHEMA IF NOT EXISTSpolicyd` DEFAULT CHARACTER SET utf8 COLLATE utf8generalci;

USE policyd;

CREATE TABLE IF NOT EXISTS ratelimit ( username VARCHAR(128) NOT NULL COMMENT 'sender address (SASL username)', quota INT(10) UNSIGNED NOT NULL DEFAULT '0' COMMENT 'limit', used INT(10) UNSIGNED NOT NULL DEFAULT '0' COMMENT 'current recipient counter', rate INT(10) UNSIGNED DEFAULT '0' COMMENT 'seconds after which the counter gets reset', rdate DATETIME NOT NULL DEFAULT CURRENTTIMESTAMP COMMENT 'datetime when counter was reset', PRIMARY KEY (username)) ENGINE = InnoDB DEFAULT CHARACTER SET = utf8 COLLATE = utf8general_ci; ```

Postfix configuration

Add the path of the policy-rate-limit socket to smtpd_sender_restrictions for example:

smtpd_sender_restrictions: check_policy_service { unix:/tmp/policy-rate-limit.sock, default_action=DUNNO }

check the perms of the socket, you may need chmod 666