Mandatory TLS is a mail-transport policy where messages are sent only if encrypted transport requirements are satisfied. It matters because some communications are too sensitive to permit silent fallback to unencrypted delivery.
What is Mandatory TLS?
Unlike opportunistic TLS, mandatory TLS enforces a stronger delivery rule: if the recipient side cannot meet the required security conditions, the message is not sent over insecure transport. This is useful for regulated or highly sensitive mail flows.
What Mandatory TLS Commonly Supports
Common uses include regulated email exchange, sensitive business communications, secure partner transport, and stronger confidentiality policy.
Mandatory TLS vs. Opportunistic TLS
Mandatory TLS refuses insecure fallback. Opportunistic TLS prefers encryption but may still deliver if encryption negotiation is unavailable.
Frequently Asked Questions
Why use mandatory TLS?
Because some message flows need a stronger guarantee that transport protection will be present every time.
What is the tradeoff?
Stricter transport requirements can create delivery failures if the receiving side is not configured compatibly.
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