
A concrete walkthrough for enabling MTA-STS on Microsoft 365 and Exchange Online. Learn why EXO cannot serve the policy file, which DNS records and subdomain you need, how to list the…

DANE anchors a mail server TLS certificate in DNS through DNSSEC and protects against downgrade and certificate spoofing. This guide explains what DANE and TLSA are, how certificate binding works,…

A directory harvest attack, DHA for short, collects valid email addresses over SMTP for later spam and phishing waves. This guide explains what a directory attack is, how it differs from address…