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.