Many Zimbra administrators have setup TLS encryption to protect their users’ login credentials and email in transit. But TLS is a complex standard, and often unknowingly misconfigured. Deploying TLS correctly does not require a university degree in cryptography, but rather a working knowledge of some key concepts and awareness of pitfalls to avoid. And, with […]
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Configuring Fail2Ban on Zimbra
This article is a how-to guide on installing Fail2Ban to block attacking hosts using a null route or blackhole routes. This can help mitigate brute force attacks on Zimbra. Especially brute force attacks on SMTP are very common. Prerequisite: Fail2ban has been tested in combination with netfilter-persistent and iptables. If you use ufw or firewalld […]
Zimbra with Let’s Encrypt Certificates a step-by-step guide (update)
This article is a step-by-step instruction on setting up a Zimbra with Let’s Encrypt certificates. If you are running a multi server installation of Zimbra it is recommended you set-up a dedicated VM for obtaining the Let’s Encrypt certificate and follow this blog. Prerequisites This guide assumes you are using Ubuntu 20 and you have […]
Zimbra SkillZ: Add an External Email Warning in Zimbra via the Admin Console
Hello Zimbra Customers, Partners & Friends, New with 9.0.0 Patch 25, you can add an external email warning in Zimbra using the Admin Console. An external email warning message alerts you when you receive email from an external domain. This is done using a Sieve filter, and it can be enabled per account, COS, domain […]
Zimbra SkillZ: Using Sieve Filters on Zimbra via the Admin Console
Hello Zimbra Customers, Partners & Friends, This article is a short how-to on using Sieve filters on Zimbra via the Admin Console. Sieve is a powerful scripting language for filtering incoming email messages. While Zimbra supports user set incoming email filters, the Sieve filters are meant to be set up and installed by administrators. Here’s […]
Zimbra SkillZ: Legal Intercept in Zimbra (updated April 2023)
Hi Zimbra Customers, Partners & Friends, Did you know that Zimbra has a Legal Intercept for Law Enforcement feature? This is used to obtain copies of email messages that are sent, received or saved as drafts from targeted accounts. Intercepted messages are sent to a designated shadow email address. Legal Intercept can be configured to […]