Adding TLS Peers

  1. Go to Inbound Protection > Connection Filtering > Transport Layer Security (TLS) Peers.
  2. Select a managed domain.
  3. Click Add to add a TLS peer for the selected domain.
  4. Specify a sender domain, IP address, or CIDR block as TLS Peer.
  5. Set the Security level to one of the following:
    • 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 Trend Micro Email Security MTA, configure your firewall to accept email messages from the following Trend Micro Email Security IP address / CIDR blocks:

        • North America, Latin America and Asia Pacific:

          18.208.22.64/26

          18.208.22.128/25

          18.188.9.192/26

          18.188.239.128/26

        • Europe, the Middle East and Africa:

          18.185.115.0/25

          18.185.115.128/26

          34.253.238.128/26

          34.253.238.192/26

        • Australia and New Zealand:

          13.238.202.0/25

          13.238.202.128/26

  6. Select Enabled to have Trend Micro Email Security apply your specified TLS security level to the new peer.
  7. Click Save.