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Important Announcements

Cisco Secure Email Add-Ins No Longer Supported on Microsoft Outlook 2019

This is to inform you that, effective October 14, 2025, Microsoft Outlook 2019 is no longer supported for the Secure Email Encryption Service Add-In and Secure Email Submission Add-In.

To continue using these Add-Ins, we recommend upgrading to Microsoft 365. Starting October 2025, download and install the new manifest for:

- Secure Email Encryption Service Add-In from the CRES Admin Dashboard

- Secure Email Submission Add-In from the Cisco Software Download Portal

After downloading the manifests, follow the instructions provided in the Submission and Encryption Add-In guides. For more information, see: Cisco Email Encryption - End-User Guides.

TLS 1.0/1.1 Deprecation from AsyncOS for Secure Email Gateway, Starting version 16.5

We would like to inform you that starting with the AsyncOS 16.5 release, TLS versions 1.0 and 1.1 will no longer be available as configuration options in both the CLI and GUI.

To ensure secure email delivery and receipt, you should use TLS versions 1.2 and 1.3. These versions can be configured via the sslconfig CLI command or through the System Administration > SSL Configuration menu in the user interface.

For detailed instructions on updating TLS versions, please refer to the “System Administration” section of the User Guide for AsyncOS 16.0.x for Cisco Secure Email Gateway.

 

Forum Posts

  Important: Migrate from Secure Email Virtual C100V Models to Avoid McAfee-Related Issues Dear Valued Customer, We are reaching out to ensure your Cisco Secure Email environment continues to operate at optimal performance and reliability. As workloa...

dmccabej by Cisco Employee
  • 1663 Views
  • 2 replies
  • 0 Helpful votes

Hi, We are experiencing an issue with outbound mail flow through Cisco ESA. Emails are sent from Microsoft 365, relayed via ESA, and then delivered to an external domain. Mail flow is as follows:user@domain.com → Microsoft 365 → Cisco ESA → recipient...

Resolved! SNI support on ESA

Hi all,I am attempting to integrate a 3rd party encryption service with Cisco ESA.The expected mail flow route is 365 -> ESA -> encryption server -> ESA -> final delivery.My encryption server requires SMTP Auth, SNI and SSL/TLS.I have a TLS enforced ...

I have 2 cisco ESA's one is in production ESA01 and another in build state - ESA02and I have about 38 domains that use ESA for sending/recieving emaisl via ESA01When I am am needing a cert for ESA for TLS communications for sending and recieving - wh...

GRajuK by Visitor
  • 251 Views
  • 0 replies
  • 0 Helpful votes

Has anyone used the API for remediation tasks? We recently had a situation where we needed to remediate over 100 different domains. Tiring, to say the least, using the GUI.

kmabus by Visitor
  • 448 Views
  • 3 replies
  • 0 Helpful votes

Hi,I’m trying to understand the exact behavior of the header **X-ESA-CF-TLS-Mandatory** on an ESA and would appreciate clarification from Cisco or anyone with deep ESA experience.What I am trying to achieveWe externally add the header:X-ESA-CF-TLS-Ma...

M1ssi by Frequent Visitor
  • 1213 Views
  • 4 replies
  • 1 Helpful votes

I need to quarantine letters with nested archives (.zip in .zip, .rar in .zip etc) in attachments. Archives with all other attachments must send clearly. How can I configure Content or Message filter for this case? I try to replays 5 with 1 in Scan B...

mofnoc by Level 1
  • 729 Views
  • 2 replies
  • 0 Helpful votes