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

To configure TLS, go to HES console > Inbound Protection or Outbound Protection > Transport Layer Security (TLS) Peers. For detailed procedure, refer to this document: Adding TLS Peers.

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

TERMDETAILS
TLS peerHES 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
 

To ensure messages can be received from the HES MTA, configure your firewall to accept email messages from the following HES 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:

• 54.86.63.64/26
• 54.219.188.0/26
• 54.219.191.0/25

 
Status
  • Enabled: HES applies your specified TLS configuration to the peer
  • Disabled: HES does not apply your specified TLS configuration to the peer

Otherwise, the default TLS configuration applies.

Default (TLS Peer)

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

  • Domain is not on the peer list
  • Domain is on the peer list, but is not enabled
Keywords: Transport Layer Security,send mail over TLS,HES use TLS,Opportunistic TLS mode,STARTTLS command,EHLO command,sending mails using TLS,forced TLS