Unwanted email, also known as spam, fills the average Inbox at a very high rate. A large volume of spam consumes bandwidth, degrades employee productivity, and wastes network resources.
Commercial mail filters use many methods to find spam. Blacklists keep a list of domains that are used by known spam sources or are open relays for spam. Content filters search for key words in the header and body of email messages. URL detection compares a list of domains used by known spam sources to the advertised link in the body of the email message. All of these procedures scan each individual email message. Attackers can easily bypass those fixed algorithms. They can mask the sender address to bypass a blacklist, change key words, embed words in an image, or use multiple languages. They can also create a chain of proxies to disguise the advertised URL.
spamBlocker uses a combination of rules, pattern matching, and sender reputation to accurately identify and block spam messages and keep them away from your email server. spamBlocker uses IPv4 to connect to the spamBlocker server. If your Firebox is configured for IPv6, you must configure the external interface with both an IPv4 address and an IPv6 address.
spamBlocker helps you control inbound spam. We recommend that you also configure the SMTP proxy to prevent mail relay through your mail server. For more information, see Protect Your SMTP Server from Email Relaying.