Related Topics
About the POP3-Proxy
POP3 (Post Office Protocol v.3) is a protocol that moves email messages from an email server to an email client on a TCP connection over port 110. With POP3, an email client contacts the email server and checks for any new email messages. If it finds a new message, it downloads the email message to the local email client. After the message is received by the email client, the connection is closed.
With a POP3-proxy filter you can:
- Adjust timeout and line length limits to make sure the POP3-proxy does not use too many network resources, and to prevent some types of attacks.
- Customize the deny message that is sent to a user when content or attachments are stripped from an email sent to that user.
- Filter content embedded in email with MIME types.
- Block specified path patterns and URLs.
To add the POP3-proxy to your Firebox configuration, see Add a Proxy Policy to Your Configuration.
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 POP3-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 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 POP3.
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 POP3-proxy, you can configure these categories of settings for a proxy action:
- POP3-Proxy: General Settings
- POP3-Proxy: Authentication
- POP3-Proxy: Content Types
- POP3-Proxy: Filenames
- POP3-Proxy: Headers
- POP3-Proxy: AntiVirus
- POP3-Proxy: Deny Message
- POP3-Proxy: Proxy and AV Alarms
- POP3-Proxy: APT Blocker
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:
Policy Tab
To set access rules and other options, select the Policy tab.
- POP3-proxy 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.
- Proxy action — Select the proxy action to use for this policy. You can also edit the rulesets for proxy actions.
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, see Set Logging and Notification Preferences. - If you set the POP3-proxy connections are drop-down list (on the Policy tab) to Denied or Denied (send reset), you can block sites that try to use POP3.
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.
Advanced Tab
You can also configure these options in your proxy definition:
- Set an Operating Schedule
- Add a Traffic Management Action to a Policy
- Set ICMP Error Handling
- Apply NAT Rules (Both 1-to-1 NAT and dynamic NAT are enabled by default in all policies.)
- Set Connection Rate Limits
- Enable QoS Marking and Prioritization in a Policy
- Set the Sticky Connection Duration for a Policy
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, see About Proxy Actions.
For the POP3-proxy, you can configure these categories of settings for a proxy action: