In Zimbra you can optionally enable Postscreen as an additional Anti-SPAM strategy. Postscreen will offer additional protection against mail server overload. One postscreen process handles multiple inbound SMTP connections and decides which clients may talk to a Post-fix SMTP server process. By keeping spambots away, postscreen leaves more SMTP server processes available for legitimate clients […]
Archive | PowerTips – Admins
Update Zimbra TLS cipher suites to disable Diffie-Hellmann
This blog post is outdated since Zimbra version 9.0.0.P34, 8.8.15.P41, 10.0.2 where Zimbra introduced OpenSSL FIPS. Please follow the updated steps at https://wiki.zimbra.com/wiki/Cipher_suites. In a previous blog and wiki we have shown how to configure Zimbra with a strong TLS configuration. Since encryption is always evolving we have updated the previous blog and wiki to […]
Did you know? SELinux is not a Zimbra feature
This blog is about something that is not a Zimbra feature, yes you read it correctly, usually on the blog we highlight new or existing features. But this blog is a little different. Every now and then people write in the Zimbra forums or comment on blog posts saying they run Zimbra with SELinux in […]
Zimbra not affected by critical OpenSSL issue
The OpenSSL project is releasing a critical fix for OpenSSL version 3.x. Zimbra is using OpenSSL version 1.1.1q which is an older still supported version of OpenSSL. The version in Zimbra is not affected by the fix, which means no patches are needed for Zimbra. You should install operating system security updates and other 3rd […]
Did you know? Basic Authentication will be disabled in Exchange Online
Did you know that as of this month Microsoft will randomly select customers and disable Basic Authentication on their Exchange Online services? While from a pure security perspective username and password authentication is outdated, you may still have issues with devices that can only support username and password authentication. For example legacy business applications, multifunction […]
Zimbra installation integrity check
The script in this article allows Zimbra administrators to create checksums of all the files in a Zimbra installation. The output of the script can be used to identify unintended changes and newly created files. Such changes can for example be caused by hackers. You can use this script pro-actively by scheduling it in a […]