Zimbra Security Tip – Block Nested Spoofed “From:” Email Addresses

Email is one of the top attack vectors for getting inside an organization, and it is a known fact that we are more likely to open an email that purports to come from someone we know. The spammers of course know this too, and recently, they have been exploiting it …

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 …

Zimbra System Administration Training – September 25-27, 2018

Mission Critical Email, the leading Zimbra Certified Training Partner in the United States, will be conducting the 3-day Zimbra Administration Course on September 25 through September 27, 2018. This hands-on course, delivered interactively, online, empowers system administrators to deploy, maintain, troubleshoot and upgrade their single- and multi-server systems in accordance …

Commercial-Works and Mission Critical Email Collaborate on Successful Zimbra 8.8.9 Upgrade

Commercial-Works is a full-service national office planning, moving, logistics and furniture provider, headquartered in Ohio and with additional offices in Indiana, North Carolina, Florida and Kentucky. The Zimbra Connector for Outlook is relied on heavily by Commercial-Works employees, who have developed sophisticated email-based workflows to better manage customer, vendor and …

Zimbra Hosting on AWS – Best Practices From The Field

During the past eight months we’ve deployed a number of single- and multi-server Zimbra systems on Amazon Web Services (“AWS”).  While Zimbra has a number of Deployment Guides, they are generic by nature and do not describe how to leverage AWS features to maximize cost savings, reliability, performance and security.  …

Zimbra Unattended Upgrades – Yes or No?

Security vs. Stability One challenge facing Linux system administrators is the tradeoff between security and the potential loss of stability when considering whether or not to enable “unattended upgrades”. When enabled, the operating system self-updates and reboots as necessary whenever package updates are released. In the case of public-facing Zimbra …

Current State of The Market – Zimbra, Office 365 and Mimecast

This month (July 2018) we started selling Office 365 and Mimecast, and we expect to add more products and services in the coming weeks to further enhance customers’ mission critical email experiences. One question I’m asked frequently is: “Is Zimbra still the best email and collaboration solution for my company, …