iftop review

Reviewed by iTechGuides Editors · Editorial team · Updated Oct 2026

iftop is a free, open-source command-line bandwidth monitor for Linux network systems. It listens on a selected network interface and presents current traffic between pairs of hosts, including source and destination ports, traffic direction, bandwidth rates, totals, and short rolling averages. System administrators can use it to investigate network usage and bottlenecks directly from a terminal. Its focus is live network visibility rather than hosted monitoring or application-level analysis.

The diagnostic view provides rates over 2-, 10-, and 40-second intervals, with configurable sorting, screen filtering, and aggregation. Packet capture filters help narrow the traffic being examined, while IPv4 and IPv6 network filtering supports both address families. Hostname and service-name resolution controls can make output more readable, and promiscuous-mode monitoring is available where the environment supports it. Text output without ncurses also makes iftop suitable for command-line workflows that need machine-readable or terminal-friendly output.

Choose iftop when the priority is a quick, local view of which host pairs are consuming bandwidth on a Linux interface. Its free, open-source model and focused feature set suit troubleshooting sessions where current traffic matters more than long-term reporting. It is less appropriate for teams that need historical retention, alerts, application monitoring, SNMP or flow-protocol support, user attribution, integrations, or multi-platform coverage. Buyers seeking a broader monitoring system should choose a product built around those capabilities instead.

iftop pros and cons

• Where it wins
  • Free and open source with no paid tier
  • Shows host pairs, ports, rates, totals, and rolling averages
  • Supports filters, IPv4/IPv6, sorting, aggregation, and text output
• Where it doesn't
  • Linux-only platform support
  • No historical retention or alerting
  • No application monitoring, integrations, or user attribution

iftop fact sheet, pricing and score →

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Last updated 7 Oct 2026 · How we research and update