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Sophos Advisory: Emails being rejected

Sophos Advisory: Emails being rejected

Advisory: Emails being rejected as server configuration errors after upgrading SEA to version 4.5.3.4

Overview

Emails being rejected as server configuration errors after upgrading Sophos Email Appliance (SEA) to 4.5.3.4.

Product and Environment

Sophos Email Appliance 4.5.3.4

Issue timeline

  • 14-FEB-2023 08:00 UTC: Sophos tentatively plans to release the firmware with the fix on 16-Feb-23.
  • 14-FEB-2023 00:20 UTC: Development is working on releasing a fix for this issue
  • 11-FEB-2023: Our SEA team is currently investigating the issue.
  • 11-FEB-2023 11:20 UTC: Issue was discovered.

Impact

Emails stop working after upgrading SEA to 4.5.3.4.

Current status

Identify the issue

Please verify the below server configuration error logs in the SEA appliance maillog:

Feb 11 13:40:55 mx100 postfix/smtpd[16198]: NOQUEUE: reject: RCPT from [domain] [IP address]: 451 4.3.5 Server configuration error; from= to= proto=ESMTP helo=

Feb 11 13:40:55 mx100 postfix/smtpd[14179]: NOQUEUE: reject: RCPT from [domain] [IP address]: 451 4.3.5 Server configuration error; from= to= proto=ESMTP helo=

Possible workaround

Do any of the following and check the status:
  • Go to Configuration > Policy > SMTP Authentication > Ports and check that only port 25 is turned off.
  • Turn off SMTP authentication.
Note: If the issue is not fixed, contact Sophos Support .
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