About the SMTP-Proxy

SMTP (Simple Mail Transport Protocol) is a protocol used to send email messages between email servers and also between email clients and email servers over a TCP connection on port 25 or 465. You can use the SMTP-proxy to control email messages and email content. The proxy scans SMTP messages for a number of filtered parameters, and compares them against the rules in the proxy configuration.

The SMTP proxy supports SMTPS connections on port 465 in Fireware v12.2 and higher.

With an SMTP-proxy policy you can:

  • Adjust timeout, maximum email size, and line length limit to make sure the SMTP-proxy does not use too many network resources and can prevent some types of attacks.
  • Customize the deny message that users see when an email they try to receive is blocked.
  • Filter content embedded in email with MIME types and name patterns.
  • Limit the email addresses that email can be addressed to and automatically block email from specific senders.

To add the SMTP-proxy to your Firebox configuration, go to Add a Proxy Policy to Your Configuration.

You can also configure subscription service settings for the SMTP-proxy. For more information, go to:

Which Proxy Action To Use

When you configure a proxy policy, you must select a proxy action appropriate to the policy. For a proxy policy that allows connections from your internal clients to the internet, use the Client proxy action. For a proxy policy that allows connections to your internal servers from the internet, use the Server proxy action.

Predefined proxy actions with Standard appended to the proxy action name include recommended standard settings that reflect the latest Internet network traffic trends.

Configure the SMTP-Proxy

Settings Tab

On the Settings tab, you can set basic information about a proxy policy, such as whether it allows or denies traffic, create access rules for a policy, or configure static NAT or server load balancing. The Settings tab also shows the port and protocol for the policy, as well as an optional description of the policy. You can use the settings on this tab to set logging, notification, automatic blocking, and timeout preferences.

SD-WAN Tab

On the SD-WAN tab, you can select to apply an SD-WAN action to the policy. You can also add a new SD-WAN action. For more information about SD-WAN routing, go to About SD-WAN.

SD-WAN replaces policy-based routing in Fireware v12.3 or higher.

Geolocation Tab

If Geolocation is enabled on your Firebox, on the Geolocation tab, you can select the Geolocation action for this proxy. You can also add a new Geolocation action. For more information about Geolocation, go to Configure Geolocation.

To apply a Geolocation action in a policy:

  1. Select the Geolocation tab.
  2. From the Geolocation Control Action drop-down list, select a Geolocation action.
    Or, to create a new Geolocation action, click Add.
  3. Click Save.

The Geolocation tab is available in Fireware 12.3 or higher.

Application Control Tab

If Application Control is enabled on your Firebox, you can set the action this proxy uses for Application Control.

  1. Select the Application Control tab.
  2. From the Application Control Action drop-down list, select an application control action to use for this policy, or create a new action.
  3. (Optional) Edit the Application Control settings for the selected action.
  4. Click Save.

For more information, go to Enable Application Control in a Policy.

Traffic Management Tab

On the Traffic Management tab, you can select the Traffic Management action for the policy. You can also create a new Traffic Management action. For more information about Traffic Management actions, go to Define a Traffic Management Action and Add Traffic Management Actions to a Policy.

To apply a Traffic Management action in a policy:

  1. Select the Traffic Management tab.
  2. From the Traffic Management Action drop-down list, select a Traffic Management action.
    Or, to create a new Traffic Management action, select Create new and configure the settings as described in the topic Define a Traffic Management Action.
  3. Click Save.

Proxy Action Tab

You can choose a predefined proxy action or configure a user-defined proxy action for this proxy. For more information about how to configure proxy actions, go to About Proxy Actions.

To configure the proxy action:

  1. Select the Proxy Action tab.
  2. From the Proxy Action drop-down list, select the proxy action to use for this policy.
    For information about proxy actions, go to About Proxy Actions.
  3. Click Save.

For the SMTP-proxy, you can configure these categories of settings for a proxy action:

Scheduling Tab

On the Scheduling tab, you can specify an operating schedule for the policy. You can select an existing schedule or create a new schedule.

  1. Select the Scheduling tab.
  2. From the Schedule Action drop-down list, select a schedule.
    Or, to create a new schedule, select Create New and configure the settings as described in the topics Create Schedules for Firebox Actions and Set an Operating Schedule.
  3. Click Save.

Advanced Tab

The Advanced tab includes settings for NAT, QoS, multi-WAN, and ICMP options.

To edit or add a comment to this proxy policy configuration, type the comment in the Comment text box.

For more information on the options for this tab, go to:

Policy Tab

To set access rules and other options, select the Policy tab.

Properties Tab

On the Properties tab, you can configure these options:

  • To edit or add a comment to this policy configuration, type the comment in the Comment text box.
  • To define the logging settings for the policy, click Logging.
    For more information, go toSet Logging and Notification Preferences.
  • If you set the SMTP-proxy connections are drop-down list (on the Policy tab) to Denied or Denied (send reset), you can block sites that try to use SMTP.
    For more information, go to Block Sites Temporarily with Policy Settings.
  • To change the idle timeout that is set by the Firebox or authentication server, go to Set a Custom Idle Timeout.

Advanced Tab

 On the Advanced tab, you can also configure these options in your proxy definition:

Configure the Proxy Action

You can choose a predefined proxy action or configure a user-defined proxy action for this proxy. For more information about how to configure proxy actions, go to About Proxy Actions.

For the SMTP-proxy, you can configure these categories of settings for a proxy action:

Related Topics

About Proxy Policies and ALGs

Configure the SMTP-Proxy to Quarantine Email