Quickly see which hosts and ports eat your network link from the terminal. 05.07.2026 | reading time: 2 min A saturated link needs a fast diagnosis; iftop shows the admin, live in the terminal, which hosts and ports consume bandwidth so he can decide what to throttle or investigate. Hands-on: find the heavy talker Imagine a web server that feels slow; run a live check and inspect the top connections with a short text dump: ```bash sudo iftop -i eth0 -P -n -t -s 5 ``` The command prints a brief text snapshot; a sample trimmed output might look like: ```text Interface: eth0 (10.0.0.5) TX: 1.2Mb RX: 800Kb 192.168.1.50:52344 -> 10.0.0.5:443 120Kb 80Kb 60Kb 10.0.0.5:22 -> 192.168.1.2:54000 10Kb 5Kb 1Kb ``` Options that answer common questions Control what you see: use -i to pick the interface; -P to show ports; -n and -N to avoid hostname or service name resolution; -B to show bytes instead of bits; -t for text output and -s to run for a fixed number of seconds; -p disables promiscuous mode and -f lets the admin apply a pcap filter; combine them to get concise, scriptable snapshots. Where iftop earns its keep Use iftop for quick per-host and per-port bandwidth checks on a machine; it is perfect for spotting a few noisy peers but not for deep packet analysis or historic long-term graphs, so pair it with capture or logging tools for follow‑up. Wrap-up and next moves Run iftop, spot the culprit, then capture or throttle as needed; to sharpen diagnostic skills pursue deeper practice and consider certification such as CompTIA Linux+ or LPIC-1 and intensive exam preparation at bitsandbytes.academy to level up system and network troubleshooting. Join Bits & Bytes Academy First class LINUX exam preparation. network utilities troubleshooting infrastructure This page was created with the help of AI.
