---
title: "smtp: Generate SMTP messages (emails) from logs"
url: "https://axoflow.com/docs/axosyslog-core/4.28/chapter-destinations/configuring-destinations-smtp/"
last_modified: "2026-08-02T11:39:11+02:00"
---

> For the complete documentation index, see [llms.txt](https://axoflow.com/docs/axosyslog-core/4.28/llms.txt).

# smtp: Generate SMTP messages (emails) from logs

The destination is aimed at a fully controlled local, or near-local, trusted SMTP server. The goal is to send mail to trusted recipients, through a controlled channel. It hands mails over to an SMTP server, and that is all it does, therefore the resulting solution is as reliable as sending an email in general. For example, AxoSyslog does not verify whether the recipient exists.

The `smtp()` driver sends email messages triggered by log messages. The `smtp()` driver uses SMTP, without needing external applications. You can customize the main fields of the email, add extra headers, send the email to multiple recipients, and so on.

The `subject()`, `body()`, and `header()` fields may include macros which get expanded in the email. For more information on available macros see [Macros of AxoSyslog](https://axoflow.com/docs/axosyslog-core/4.28/chapter-manipulating-messages/customizing-message-format/reference-macros/index.md).

The `smtp()` driver has the following required parameters: `host()`, `port()`, `from()`, `to()`, `subject()`, and `body()`. For the list of available optional parameters, see [smtp() destination options](https://axoflow.com/docs/axosyslog-core/4.28/chapter-destinations/configuring-destinations-smtp/reference-destination-smtp/index.md).

## Prerequisites

- AxoSyslog version 3.4 or later.
- This feature requires a separate module. Install the `axosyslog-mod-smtp` package on [Debian/Ubuntu](https://axoflow.com/docs/axosyslog-core/4.28/install/debian-ubuntu/index.md), or the `axosyslog-smtp` package on [RHEL and compatible distributions](https://axoflow.com/docs/axosyslog-core/4.28/install/rhel-fedora-almalinux/index.md). If the module isn’t installed, AxoSyslog fails to start with an [`unexpected LL_IDENTIFIER` error](https://axoflow.com/docs/axosyslog-core/4.28/chapter-troubleshooting-syslog-ng/unexpected-ll-identifier/index.md).

## Declaration:

```shell
   smtp(host() port() from() to() subject() body() options());
```

## Example: Using the smtp() driver

The following example defines an `smtp()` destination using only the required parameters.

```shell
   destination d_smtp {
        smtp(
            host("localhost")
            port(25)
            from("alert service" "noreply@example.com")
            to("Admin #1" "admin1@example.com")
            subject("[ALERT] Important log message of $LEVEL condition received from $HOST/$PROGRAM!")
            body("Hi!\nThe alerting service detected the following important log message:\n $MSG\n-- \n")
        );
    };
```

The following example sets some optional parameters as well.

```shell
   destination d_smtp {
        smtp(
            host("localhost")
            port(25)
            from("syslog-ng alert service" "noreply@example.com")
            to("Admin #1" "admin1@example.com")
            to("Admin #2" "admin2@example.com")
            cc("Admin BOSS" "admin.boss@example.com")
            bcc("Blind CC" "blindcc@example.com")
            subject("[ALERT] Important log message of $LEVEL condition received from $HOST/$PROGRAM!")
            body("Hi!\nThe syslog-ng alerting service detected the following important log message:\n $MSG\n-- \nsyslog-ng\n")
            header("X-Program", "$PROGRAM")
            );
    };
```

## Example: Simple email alerting with the smtp() driver

The following example sends an email alert if the eth0 network interface of the host is down.

```shell
   filter f_linkdown {
        match("eth0: link down" value("MESSAGE"));
    };
    destination d_alert {
        smtp(
            host("localhost") port(25)
            from("syslog-ng alert service" "syslog@localhost")
            reply-to("Admins" "root@localhost")
            to("Ennekem" "me@localhost")
            subject("[SYSLOG ALERT]: eth0 link down")
            body("Syslog received an alert:\n$MSG")
            );
    };

    log {
        source(s_local);
        filter(f_linkdown);
        destination(d_alert);
    };
```

---

[smtp() destination options](https://axoflow.com/docs/axosyslog-core/4.28/chapter-destinations/configuring-destinations-smtp/reference-destination-smtp/index.md)

Last modified August 2, 2026: [Adds required modules/packages to install and destination pages (553d6d9b)](https://github.com/axoflow/axosyslog-core-docs/commit/553d6d9be9a0e3ef444e62cc5351dd2ac764f01d)