On the recordRead 4 Oct 202613 facts
iftop
Plans and prices
iftop
Free
GPL-licensed software; requires sufficient permissions to monitor network traffic on the interface
Read 4 Oct 2026 · sources.debian.org
On the record
- Configuration
- iftop can read settings from a configuration file, defaulting to ~/.iftoprc when no alternate file is specified.sources.debian.org · read 4 Oct 2026
- Filtering
- It supports packet filter code and display filters, with display filters affecting what is shown rather than what is captured.sources.debian.org · read 4 Oct 2026
- Integration
- The manual lists tcpdump, pcap, and driftnet as related tools; it does not state integrations with external services.sources.debian.org · read 4 Oct 2026
- Maker
- The manual names Paul Warren as the author.sources.debian.org · read 4 Oct 2026
- Network support
- Configuration options include an IPv4 network boundary and display of link-local IPv6 traffic.sources.debian.org · read 4 Oct 2026
- Notable limitation
- After changing the capture filter, existing display entries may remain for up to 40 seconds because the display reflects a recent capture window.sources.debian.org · read 4 Oct 2026
- Permissions
- iftop must be run with sufficient permissions to monitor all network traffic on the interface.sources.debian.org · read 4 Oct 2026
- Promiscuous mode
- iftop can put the interface into promiscuous mode to capture traffic between other hosts on the same network segment.sources.debian.org · read 4 Oct 2026
- Purpose
- iftop displays current bandwidth usage by pairs of hosts on a network interface.sources.debian.org · read 4 Oct 2026
- Security and license
- The manual identifies iftop as free software under the GNU General Public License, version 2 or any later version, and provides it without warranty.sources.debian.org · read 4 Oct 2026
- Terminal output
- A text interface without ncurses is available, with options to print a single output after a specified number of seconds and limit the number of lines.sources.debian.org · read 4 Oct 2026
- Traffic capture
- iftop listens on a named interface or, if none is specified, the first interface it finds that looks like an external interface.sources.debian.org · read 4 Oct 2026
- Traffic views
- The display can show host names, port numbers, bandwidth bars, totals, and traffic rates averaged over 2, 10, and 40 seconds.sources.debian.org · read 4 Oct 2026
