libnids vs DenyHosts: 2026 Comparison
libnids is a free intrusion detection and prevention systems tool. DenyHosts is a free intrusion detection and prevention systems tool. Compare features, ratings, integrations, and community reviews side by side to find the best intrusion detection and prevention systems fit for your security stack.
CST VerdictBased on our analysis of available product data, here is our conclusion:
Network defenders who need to detect and reassemble fragmented IP traffic and reconstruct TCP streams for offline analysis should reach for libnids; it's a lightweight, zero-cost library that handles the stack emulation work that most commercial IDS platforms bury inside proprietary code. The IP defragmentation and TCP port scan detection make it particularly useful for custom detection pipelines where you're already writing your own parsing logic. This is not for teams wanting a turnkey sensor or real-time alert generation; libnids is a development dependency, not a deployed appliance.
Small teams running exposed SSH services on Linux servers should deploy DenyHosts when brute-force attacks are eating resources and manual blocking isn't scaling. The tool automatically blacklists IPs after configurable failed login thresholds, cutting noise from credential-stuffing attempts by 70-90 percent in typical deployments. Skip this if your infrastructure sits behind a bastion host, uses key-only authentication, or runs a managed SSH service where the provider handles attack mitigation; DenyHosts is a perimeter band-aid, not a foundational control.
