What are gateway spam filters?

Gateway spam filters are positioned at the network perimeter, processing all inbound email before it reaches the internal mail server. They act as the first line of defense for organizations.

Products like Proofpoint, Mimecast, Barracuda Email Security Gateway, and Cisco Email Security are gateway solutions. They receive mail via MX records pointing to their systems, filter it, and forward clean messages to the organization's mail server.

Gateway filters offer centralized control, detailed logging, and the ability to apply organization-wide policies. They handle malware scanning, phishing detection, spam filtering, and data loss prevention in one place.

For senders, gateway filters represent an additional layer beyond the mailbox provider's own filtering. A message must pass both the gateway and the final destination's filters.

The gateway is the outer harbor wall. Ships must pass through before approaching the inner docks.