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. It usually uses a TCP connection on Port 25. 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.

With an SMTP-proxy filter 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, see Add a Proxy Policy to Your Configuration.

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

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

These sections describe the SMTP-Proxy configuration tabs in Fireware Web UI.

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 policy-based routing, 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.

Connections are — Specify whether connections are Allowed, Denied, or Denied (send reset) and define who appears in the From and To list (on the Policy tab of the proxy definition). See Set Access Rules for a Policy.
Use policy-based routing — See Configure Policy-Based Routing.
You can also configure static NAT or configure server load balancing. See Configure Static NAT and Configure Server Load Balancing.
To define the logging settings for the policy, configure the settings in the Logging section.
For more information, see Set Logging and Notification Preferences.
If you set the Connections are drop-down list to Denied or Denied (send reset), you can block sites that try to use SMTP.
For more information, see Block Sites Temporarily with Policy Settings.
To change the idle timeout that is set by the Firebox or authentication server, see Set a Custom Idle Timeout.

Application Control Tab

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

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

For more information, see 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, see Define a Traffic Management Action in v11.8.x and Lower and Add a Traffic Management Action to a Policy.

To apply a Traffic Management action in a policy:

Select the Traffic Management tab.
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 in v11.8.x and Lower.
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, see About Proxy Actions.

To configure the proxy action:

Select the Proxy Action tab.
From the Proxy Action drop-down list, select the proxy action to use for this policy.
For information about proxy actions, see About Proxy Actions.
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.

Select the Scheduling tab.
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.
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, see:

About the SMTP-Proxy

Which Proxy Action To Use

Configure the SMTP-Proxy

Settings Tab

Application Control Tab

Traffic Management Tab

Proxy Action Tab

Scheduling Tab

Advanced Tab

Policy Tab

Properties Tab

Advanced Tab

Configure the Proxy Action

See Also