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Transport Layer Security (TLS) is a protocol that helps to secure data and ensure communication privacy between endpoints. Hosted Email Security allows you to configure TLS encryption policies between Hosted Email Security and specified TLS peers. Hosted Email Security supports the following TLS protocols in descending order of priority: TLS 1.2, TLS 1.1 and TLS 1.0.

The Transport Layer Security (TLS) screen uses the following important terms:

Term

Details

TLS peer

Hosted Email Security can apply your specified TLS configuration with this domain during network communications.

Security level

  • Opportunistic:

    • Communicates using encryption if the peer supports and elects to use TLS

    • Communicates without encryption if the peer does not support TLS

    • Communicates without encryption if the peer supports TLS but elects not to use TLS

  • Mandatory:

    • Communicates using encryption if the peer supports and elects to use TLS

    • Does not communicate if the peer does not support TLS

    • Does not communicate if the peer supports TLS but elects not to use TLS

      Important:

      To ensure messages can be received from the Hosted Email Security MTA, configure your firewall to accept email messages from the following Hosted Email Security IP address / CIDR blocks:

      Europe, the Middle East, Africa

      • 52.48.127.192/26

      • 52.58.62.192/26

      • 52.58.63.0/25

      All other regions

      • 54.219.191.0/25

      • 54.219.188.0/26

      • 54.86.63.64/26

Status

  • Enabled: Hosted Email Security applies your specified TLS configuration to the peer

  • Disabled: Hosted Email Security does not apply your specified TLS configuration to the peer

    Instead, the "Default" TLS configuration applies.

Default (TLS Peer)

This configuration applies to all domains that meet any of the following criteria:

  • Domain is not in the peer list

  • Domain is in the peer list, but is not enabled
Parent topic: Inbound and Outbound Protection