Overview of Mail Filtering

Definition

Mail filtering checks IP addresses and filters mail content using following functions:

• IP address check
• Mail content filtering

Objective

Mail filtering addresses the following issues:

• Junk email, which is unsolicited and includes advertisements and viruses. For end users, junk email wastes their time and may infect their systems with viruses. For Internet Service Providers (ISPs), junk email may overwhelm their mail servers, which degrades network performance.
• Anonymous email, which omits legitimate sender addresses and may contain illegitimate information.
• Leaks of sensitive information, which includes those related to technology-intensive, financial, and public companies and affairs.

To tackle these problems, the FW offers the following configurations:

• Configuring a Mail Address Group, which reduces the bandwidth consumed by junk email and prevents the mail servers from being blacklisted by their supervisor ISP for frequently forwarding massive junk email.
• Configuring Anti-Spam Based on the IP Address of the SMTP Server, which reduces the impact of non-work-related information brought about by anonymous email.
• Configuring Anonymous Email Check and Configuring Email Address Checks, which prevent information leaks by controlling the mail sending permissions and the size of the sent email attachments.