---
name: "Mail::MtPolicyd::Plugin::SMTPVerify"
section: "3pm"
platform: "linux"
package: "mtpolicyd"
version: "2.05-1.2"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/Mail::MtPolicyd::Plugin::SMTPVerify"
---

# Mail::MtPolicyd::Plugin::SMTPVerify(3pm)

mtpolicyd plugin for remote SMTP address checks

## NAME

Mail::MtPolicyd::Plugin::SMTPVerify - mtpolicyd plugin for remote SMTP address checks

## VERSION

version 2.05

## DESCRIPTION

This plugin can be used to do remote SMTP verification of addresses.

## Example

To check if the recipient exists on a internal relay and mailbox is able to receive a message of this size:

```
  <Plugin smtp-rcpt-check>
    module = "SMTPVerify"

    host = "mail.company.internal"
    sender_field = "sender"
    recipient_field = "recipient"
    # send SIZE to check quota
    size_field = "size"
    temp_fail_action = "defer %MSG%"
    perm_fail_action = "reject %MSG%"
  </Plugin>
```

Do some very strict checks on sender address:

```
  <Plugin sender-sender-check>
    module = "SMTPVerify"
    # use a verifiable address in MAIL FROM:
    sender = "horst@mydomain.tld"
    recipient_field = "sender"
    no_starttls_action = "reject sender address does not support STARTTLS"
    temp_fail_action = "defer sender address failed verification: %MSG%"
    perm_fail_action = "reject sender address does not accept mail: %MSG%"
  </Plugin>
```

Or do advanced checking of sender address and apply a score:

```
  <Plugin sender-sender-check>
    module = "SMTPVerify"
    # use a verifiable address in MAIL FROM:
    sender = "horst@mydomain.tld"
    recipient_field = "sender"
    check_tlsa = "on"
    check_openpgp = "on"
    temp_fail_score = "1"
    perm_fail_score = "3"
    has_starttls_score = "-1"
    no_starttls_score = "5"
    has_tlsa_score = "-3"
    has_openpgp_score = "-3"
  </Plugin>
```

Based on the score you can later apply greylisting or other actions.

## Configuration

### Parameters

The module takes the following parameters:

- (uc\_)enabled (default: on)

  Enable/disable this check.

- host (default: empty)

  If defined this host will be used for checks instead of a MX.

- port (default: 25)

  Port to use for connection.

- check\_tlsa (default: off)

  Set to 'on' to enable check if an TLSA record for the MX exists.

  This requires that your DNS resolver returns the AD flag for DNSSEC secured records.

- check\_openpgp (default: off)

  Set to 'on' to enable check if an OPENPGPKEY records for the recipients exists.

- sender\_field (default: recipient)

  Field to take the MAIL FROM address from.

- sender (default: empty)

  If set use this fixed sender in MAIL FROM instead of sender\_field.

- recipient\_field (default: sender)

  Field to take the RCPT TO address from.

- size\_field (default: size)

  Field to take the message SIZE from.

- perm\_fail\_action (default: empty)

  Action to return if the remote server returned an permanent error for this recipient.

  The string "%MSG%" will be replaced by the smtp message:

  ```
    perm_fail_action = "reject %MSG%"
  ```

- temp\_fail\_action (default: empty)

  Like perm\_fail\_action but this message is returned when an temporary error is returned by the remote smtp server.

  ```
    temp_fail_action = "defer %MSG%"
  ```

- perm\_fail\_score (default: empty)

  Score to apply when a permanent error is returned for this recipient.

- temp\_fail\_score (default: empty)

  Score to apply when a temporary error is returned for this recipient.

- has\_starttls\_score (default: emtpy)

  - no\_starttls\_score (default: emtpy)

  Score to apply when the smtp server of the recipient announces support for STARTTLS extension.

- has\_tlsa\_score (default: empty)

  - no\_tlsa\_score (default: empty)

  Score to apply when there is a TLSA or no TLSA record for the remote SMTP server.

- has\_openpgp\_score (default: empty)

  - no\_openpgp\_score (default: empty)

  Score to apply when a OPENPGPKEY record for the recipient exists or not exists.

## AUTHOR

Markus Benning \<ich@markusbenning.de\>

## COPYRIGHT AND LICENSE

This software is Copyright (c) 2014 by Markus Benning \<ich@markusbenning.de\>.

This is free software, licensed under:

```
  The GNU General Public License, Version 2, June 1991
```