https://www.pistack.xyz/tags/mta-sts/ Recent content in Mta-Sts on Pi Stack Hugo en-us Thu, 14 May 2026 00:00:00 +0000 https://www.pistack.xyz/posts/2026-05-14-self-hosted-mta-sts-policy-servers-resolver-tlspol-sts-mate-guide/ Thu, 14 May 2026 00:00:00 +0000 https://www.pistack.xyz/posts/2026-05-14-self-hosted-mta-sts-policy-servers-resolver-tlspol-sts-mate-guide/ <p>Email encryption in transit is critical for protecting sensitive communications, but traditional SMTP has a fundamental flaw: it silently falls back to plaintext when TLS negotiation fails. An active attacker can exploit this by stripping TLS capabilities during the SMTP handshake, intercepting all email content. MTA-STS (Mail Transfer Agent Strict Transport Security, RFC 8461) solves this by allowing domain owners to publish a policy that mandates TLS for inbound mail, preventing downgrade attacks.</p>