What are email security gateways?

Email security gateways filter messages before reaching user mailboxes. They provide: spam filtering, malware detection, phishing protection, and data loss prevention. Gateways sit between internet and mail servers, inspecting all traffic.

Functions include: content scanning (attachments, links, text), authentication verification, sender reputation checking, encryption enforcement, and policy implementation. Enterprise gateways add: sandboxing, URL rewriting, and advanced threat protection.

Deployment: cloud-based services (Mimecast, Proofpoint), on-premise appliances (Barracuda, Cisco), or integrated with email platforms (Microsoft Defender for Office 365). Choice depends on infrastructure, compliance needs, and security requirements.