Glossary
Email gateway
A server or service at the edge of an organisation’s mail system that filters inbound and outbound messages.
ValidReach Team · Updated 2026-10-26
In practice
Gateways scan for spam and malware before mail reaches the mailboxes behind them. Some accept all recipients at the edge and sort them out later.
Verification and sending
That behaviour can make mailbox checks inconclusive for protected domains, so a verifier may return unknown or catch-all rather than a firm answer.