OSSEC vs Paessler PRTG Network Monitor

OSSEC is an open-source host-based intrusion detection system for monitoring systems and network components. It analyzes logs, checks file integrity, monitors the Windows registry, detects rootkits, and can alert users in real time or take active response actions. Monitoring can be agent-based or agentless, and a centralized server applies policies across operating systems, with server-specific overrides. Alerts can use SMTP, SMS, and syslog; active response can block an attack immediately. The system runs on Linux, OpenBSD, FreeBSD, macOS, Solaris, and Windows, and supports self-hosted and cloud environments. OSSEC and OSSEC+ use command-line management; Atomic OSSEC editions add a management console and integrations with cloud services and other tools. OSSEC+ adds machine learning, ELK integration, threat sharing, and additional rules. Free OSSEC is listed at free; OSSEC+ is also free, with registration required. Atomic OSSEC is $5 a month per device. Atomic OSSEC SaaS offers a free 14-day trial for up to 10 endpoints.

Paessler PRTG Network Monitor monitors systems, devices, network traffic, applications, and other infrastructure metrics from an on-premises installation. It runs on Windows servers and includes more than 250 preconfigured sensors, each measuring one or more aspects of a device. Monitoring tools include customizable alerts, scheduled reports, distributed monitoring, and dashboards with live status information. Paessler also lists adaptive AI-driven anomaly detection and smart sensor recommendations. PRTG provides an API for monitoring data and custom features, and can send webhook notifications to Slack and Microsoft Teams. Its free iOS and Android apps display monitoring data and send push notifications, but do not support cluster setups. The free plan covers up to 100 sensors; paid plans start at $200 per month paid annually. Each server accepts one license key, so license sizes cannot be combined on a server.