Zimbra Anti-Spam Best Practices – Updated for 2024

Each year, we read in the various data breach reports that email remains the Number One attack vector used for phishing, whaling, malware distribution and other scams. In this blog post, continuously updated since March 2019, we describe how we supplement the various open-source anti-spam capabilities that ship with Zimbra …

Using Zimbra’s DoSFilter and Failed Login Lockout Policy Together

Zimbra’s DoSFilter (Denial of Service Filter) is a mechanism to throttle or block IP addresses that have a repeated number of failed logins to your Zimbra system.  Zimbra’s Classes of Service include a Failed Login Lockout policy that will put a mailbox in Locked Out mode, hopefully before a brute …