A visual representation of a resilient business email security gateway

Resiliency is an important factor to consider when evaluating an email security solution, yet this characteristic often goes overlooked.

When choosing an email security solution, people often consider the technology it utilizes and how this technology is implemented to provide protection against current email-related threats. These are critical aspects to take into account, given that organizations are dependent on email for communications and email is currently the most popular attack vector for cybercriminals. An attribute that often remains unconsidered is resiliency or, in other words, how reliable and secure a solution is over time. Resiliency is a quality that is critical in determining if a solution can provide effective, uninterrupted protection against the myriad of dangerous attacks that constitute today’s email threat landscape.

A significant factor in determining the resiliency of a solution is the software it is comprised of and the operating system it runs on. For numerous reasons, Linux and open source software have a greater potential to achieve a very high level of security than alternative operating systems and proprietary software do. The open source development model offers inherent security advantages, making open source products and technologies secure by design. Because of the collaboration and transparency involved in the development of open source software, vulnerabilities and potential security issues are rapidly detected and fixed. As a result of this collaborative development and review process, Linux is inherently more secure than proprietary OS alternatives like MacOS or Microsoft Windows. The various security advantages associated with open source technology make email security solutions that run on Linux and utilize open source software both highly secure and highly resilient. 

Key Features of Guardian Digital's Open-Source EnGarde Cloud Email Security:

  • Highly effective protection against sophisticated new and existing email-related threats including phishing, business email compromise, malware, email spoofing and spam email
  • Rapid and highly accurate identification and quarantine of malicious email
  • Advanced machine learning and heuristics technology, Big Data techniques and broad file type analysis
  • Customizable to fit businesses’ specific demands
  • Exceptional customer support
  • Comprised of entirely open-source software and operated on an inherently secure hardened version of Linux
  • Cloud-based and highly convenient


For over a decade we’ve counted on Guardian Digital’s solutions for a more secure and reliable mail environment. I’m grateful for their years of great service — the staff is professional and prompt and has always had a quick resolution to our mail inquiries or any other issues.

-Sheldon Huey, Best Western International, Senior Operations Manager, Enterprise Email


Guardian Digital just recently decommissioned two mail systems that were running optimally for more than four years without being rebooted or adjusted beyond standard maintenance. These systems reliably routed hundreds of millions of emails over their lifetime. They offered a myriad of businesses highly effective protection against serious and evolving email-related threats including spear-phishing, business email compromise and ransomware. All of Guardian Digital’s mail systems run on a hardened version of Linux specifically developed to optimize the systems’ security and reliability over time. A combination of the inherent security of Linux, the expertise of Guardian Digital engineers, and a strong emphasis on quality and customer service results in systems that will reliably route mail virtually indefinitely. In the long run, the performance of these systems is truly unrivaled.

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