The HTTP Strict-Transport-Security response header (often abbreviated as HSTS) informs browsers that the site should only be accessed using HTTPS, and that any future attempts to access it using HTTP should automatically be converted to HTTPS. What does HSTS do for improving security? You have HSTS configured on Zimbra and have configured a correct TLS […]
Archive | PowerTips – Admins
Protecting Zimbra with Sucuri web application firewall
By Barry de Graaff on January 11, 2023 in Product News, Partners, PowerTips – Admins, Security & Privacy
You can enhance the security of your Zimbra servers by using a web application firewall (WAF). By using a web application firewall you can add the following protections to Zimbra: Geo blocking, geo fencing Blocking or allow IP addresses Emergency DDoS protection Block anonymous proxies Block top three attack countries Manage HTTP Security Headers Limited […]
Did you know? Zimbra Postscreen provides additional protection against mail server overload
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 […]
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This blog post is outdated since Zimbra version 9.0.0.P34, 8.8.15.P41, 10.0.2 where Zimbra introduced OpenSSL FIPS.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 […]