Configuring antispam settings

The AntiSpam menu item lets you configure the antispam and antivirus features of the FortiMail unit to protect your SMTP servers and email users. You can configure antispam and antivirus settings separately for incoming and outgoing email messages.

Available FortiMail features and their behavior vary by whether the email is incoming or outgoing. This is called directionality.

• Incoming email messages consist of messages sent to the SMTP servers that are protected domains of the FortiMail unit.
• Outgoing email messages consist of messages sent to recipients on domains that the FortiMail unit was not configured to protect.

For a more detailed explanation, see “Incoming versus outgoing directionality” on page 7.

Configuring incoming mail protection

The Incoming tab displays the antispam and antivirus settings for the protected domains, and enables you to change the default settings.

To edit incoming antispam and antivirus settings

1. Go to Settings > AntiSpam > Incoming.

Figure 39:Antispam incoming tab

2. To change settings, do one of the following:
   • select a domain in the table and click Edit
   • double-click the domain A dialogs appears.

Figure 40: Editing the antispam and antivirus settings

3. Select one of the following for the antispam level:
   • Unknown: No setting
   • Off: No scanning
   • Low: Good detection rate
   • Medium: Better detection rate with a small impact on system performance • High: Best detection rate with an additional impact on system performance
4. Select one of the following for the antivirus level:
   • Unknown: No setting
   • Disabled: Virus checking is off
   • Enabled: Virus checking is on
5. Click OK.

Configuring incoming actions

The Incoming Action tab lets you to select what measures the FortiMail unit will take against spam and virus-infected email coming into the domain. This tab also determines which quarantine list to use: personal or system.

To configure incoming actions

1. Go to Settings > AntiSpam > Incoming Action.
2. Configure the following: Figure 41: Editing incoming actions

AntiSpam Actions
Tag email’s subject line	Enable and then enter in the With value field the text that will appear in the subject line of the email, such as “[spam]”. The FortiMail unit will prepend this text to the subject line of spam before forwarding it to the recipient. Many email clients can sort incoming email messages into separate mailboxes, including a spam mailbox, based on text appearing in parts of email messages, including the subject line. For details, see the documentation for your email client.
Reject	Enable to reject the email and reply to the SMTP client with SMTP reply code 550.
Discard	Enable to delete the message (instead of delivering the email) without notifying the SMTP client
Quarantine	When enabled, FortiMail directs spam to the per-recipient quarantine folder. For more information, see “Viewing and managing quarantine lists” on page 125. Also configure: •    Delete messages after: Enter the number of days you want to keep the quarantined email. Enter a small enough value that will prevent the size of the quarantine from exceeding the available disk space. If you enter 0 to prevent automatic deletion of quarantined files, you must periodically manually remove old files. This option and Quarantine for review are mutually exclusive.
Quarantine to review	When enabled, FortiMail directs spam to the system quarantine folder. Both quarantine options cannot be enabled at the same time.
AntiVirus Actions
Virus scanning	Scan email for virus infection and take actions defined in the antivirus action profile.

3. Click Apply.

Configuring outgoing mail protection

After you create a protected domain, the FortiMail unit will apply default outgoing antispam and antivirus settings to it. The Outgoing tab lets you change the defaults.

To edit outgoing antispam and antivirus settings

1. Go to Settings > AntiSpam > Outgoing.

Figure 42: Editing the antispam and antivirus settings

2. Select one of the following for the antispam level:
   • Unknown: No setting
   • Off: No scanning
   • Low: Good detection rate
   • Medium: Better detection rate with a small impact on system performance • High: Best detection rate with an additional impact on system performance
3. Select one of the following for the antivirus level:
   • Unknown: No setting
   • Disabled: Virus checking is off
   • Enabled: Virus checking is on
4. Optionally, view or edit the access control link. See “Configuring access control”.
5. Click Apply.

Configuring access control

Access control rules allow specific SMTP clients to send email from your protected domains. These rules prevent your FortiMail unit from being an open relay. Open relays are often used by spammers, which could cause your unit to be blacklisted by other mail servers.

Access control rules allow, discard, reject, or relay email based on the sender, recipient, IP address, or a reverse DNS lookup of the domain name of the connecting SMTP server.

To configure access control

1. Go to Settings > AntiSpam > Outgoing.
2. Click Access control link.
   • new window appears. If you created an access control rule using the Quick Start Wizard, it will appear on the list.

Figure 43:Access control window

3. Either click New to create a new rule, or select an existing rule and click Edit.
   • dialog appears.

Figure 44:Access control rule dialog

4. Configure the access rule the same way as in the Quick Start Wizard. See “Step 6: Configuring access control rules and outgoing settings” on page 40
5. Click Create or OK.