Kerio Control 942 2021 | Premium & Recommended

Who is this for? Kerio Control 9.4.2 is ideal for SMBs (10-100 users) and IT Managed Service Providers.

It is for the administrator who wants to "set it and forget it." It lacks the flashy AI dashboards of 2024-era firewalls, but it excels at the fundamentals: routing, VPN connectivity, and simple policy enforcement. If you are an organization that requires deep packet inspection for regulatory compliance or advanced behavioral threat hunting, Kerio is likely too basic. However, for general office protection and remote worker access, it is one of the most frustration-free options available.

Recommendation: If you are currently on 9.4.0 or 9.4.1, the upgrade to 9.4.2 is essential for VPN stability and security patches. If you are looking for a new firewall, consider Kerio only if you prioritize ease-of-use over advanced AI security features.

No hardware review is complete without discussing real-world pain points. According to the official Kerio Community Forum and Reddit r/sysadmin posts from 2021: kerio control 942 2021

Issue 1: Packet Loss under High UDP Load

Issue 2: SSL Inspection breaking iOS 15 apps

Issue 3: Fan noise

1. Stability and Appliance Hardening The primary narrative surrounding the 9.4.2 update was stability. For IT administrators managing Kerio Control boxes (whether hardware appliances, virtual machines, or software instances), uptime is the metric by which they are judged. Version 9.4.2 addressed several critical memory management issues and kernel-level bugs that had plagued previous iterations. This ensured that the firewall could handle high-throughput traffic spikes without dropping packets or requiring unplanned reboots—a critical requirement for VoIP and video conferencing traffic that dominated 2021.

2. Enhanced VPN Capabilities Kerio Control has long been celebrated for its VPN solutions: the proprietary Kerio VPN Client and the industry-standard IPsec. In 9.4.2, the IPsec stack received specific attention. With the deprecation of older, less secure encryption algorithms (like DES and 3DES) across the industry, 9.4.2 ensured robust support for AES-GCM and stronger SHA-2 hashing. This allowed businesses to create site-to-site tunnels with modern cloud providers (like AWS and Azure) without compatibility errors.

3. The Web Filter and Content Awareness The update continued to refine the Kerio Control Web Filter. In an era where employees were increasingly distracted by streaming and social media during work hours, bandwidth management was crucial. The 9.4.2 engine improved the categorization of web traffic, allowing administrators to granularly block categories (e.g., "Gambling," "Social Networking," or newly emerging "Phishing" domains) with higher accuracy. This reduced false positives, a common headache for IT support teams. Who is this for

4. User Interface Refinements While the administrative interface in 9.4.2 did not undergo a total redesign (the classic Kerio UI remained), it was polished for usability. The dashboard provided real-time visualization of throughput, active VPN connections, and blocked threats. For SMBs lacking a dedicated SOC (Security Operations Center), this "at-a-glance" visibility was invaluable.

The most significant aspect of the 2021 update was the mitigation of CVE-2020-3557x (specific Kerio authentication bypass issues). It also updated the bundled OpenSSL version to 1.1.1i, patching the infamous "Zombie POODLE" and "Sweet32" attacks.