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Attention

As of March 1, 2022, the legacy Barracuda Essentials Security, Compliance, and Complete editions are no longer available for purchase. Only existing customers can renew or add users to these plans. The documentation and trainings related to these plans will no longer be available after October 30, 2022. For more information on the latest Email Protection plans, see Barracuda Email Protection.

To update your bookmarks, see the following for the latest documentation and trainings:

Note that MSP customers should continue to follow Barracuda Essentials for MSPs.

Outbound Mail Rejected By UCEProtect3

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UCEProtect is a DNS block list service consisting of three block lists that block either a single IP (dnsbl-1 Level 1), a subnet (dnsbl-2 Level 2), or an ASN (dnsbl-3 Level 3).

Barracuda Networks has observed that some organizations are using UCEProtect Level 3 as a bloc k list on their mail systems. When UCEProtect blocks AWS ASN AS16509 and your recipient organization uses UCEProtect Level 3 as a block list, they are unable to receive mail from you when you send outbound mail using the Barracuda Email Security Service. This can happen even though none of the Barracuda Email Security Service IPs are specifically blocked by UCEProtect. Unfortunately, this is out of Barracuda Networks' control. Barracuda Networks recommends the recipient organization to adjust their mail systems to follow the recommended best practices when using UCEProtect Level 3 block list.

Based on UCEProtect's recommendations, the use of Level 3 is to incorporate it into a scoring system, to give e.g. 2 points on a ‘match’ where 5 or more points trigger a spam tag. 

For more information, see:

Recipient organizations should also allow the following IP address ranges in order to receive mail from the Barracuda Email Security Service:

  • 3.24.133.128/25
  • 15.222.16.128/25
  • 35.157.190.224/27
  • 35.176.92.96/27
  • 209.222.82.0/24
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