What is inbound filtering and how is it configured?

Inbound filtering scans received email before delivery to mailboxes. It blocks spam, phishing, malware, and unwanted messages protecting your users. Configuration balances protection against false positives blocking legitimate mail.

Filtering layers typically include: connection-level checks (IP reputation, rate limiting), protocol checks (authentication verification), content scanning (spam scoring, malware detection), and user-level rules (personal filters, allowlists).

Configuration options: sensitivity thresholds, quarantine versus rejection, admin versus user control, allowlists/blocklists, and integration with threat intelligence feeds. Most organizations use provider-managed filtering (Google Workspace, Microsoft 365) rather than self-managed solutions.