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To check bandwidth usage on Linux, install vnStat and run vnstat -d for daily or vnstat -m for monthly traffic per interface; it records in the background once installed. For what is using bandwidth right now, run sudo iftop -i eth0, which lists the busiest connections. ip -s link show eth0 shows total bytes since boot without installing anything.

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Before you start

  • Bandwidth is how fast data moves (Mbit/s). Traffic is how much data moved in total (GB or TB). Received data is rx (inbound), sent data is tx (outbound).
  • On a VPS, the panel also shows monthly traffic for your server: see VPS traffic and bandwidth. The numbers inside the server can differ slightly from the panel, because they’re measured at a different point.
  • Find your interface name with ip -br link (for example eth0, ens3). Commands use sudo; as root, leave it out.

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Which tool should I use?

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How to see daily and monthly traffic with vnStat

1

Install vnStat

The vnstat service is enabled and started during installation.
2

Wait for the first data

The background service (vnstatd) adds every interface it finds and saves data every few minutes. Right after installing you’ll see “No data” until the first save.
3

Show the traffic

vnStat only knows about traffic from the moment it was installed. Use vnstat -l for a live view of the current rate, and vnstat -t for the top traffic days.

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How to see which connections use bandwidth with iftop

-n shows IP addresses instead of names (faster), -P shows ports. Each line is a connection between your server (=> sent, <= received) and a remote address, with the average rate over 2, 10 and 40 seconds. Press q to quit. For a one-off text report, for example to paste into a ticket:
This prints the top connections after 10 seconds and exits. To find which program owns a busy connection, take the port from iftop and look it up:

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How to see the current speed with nload

nload shows incoming and outgoing speed as two graphs with current, average, minimum, maximum and total. Press q to quit.

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How to check traffic without installing anything

These counters start at zero when the server boots. Rising errors or dropped values can point to a network problem.
Sudden, large outbound traffic you can’t explain may mean a compromised server sending spam or attack traffic. Check with iftop which addresses it goes to, and see what to do if your Linux server is hacked.

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Frequently asked questions

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Why does vnStat show “No data”?

The service hasn’t saved its first sample yet, or it isn’t running. Wait a few minutes and check systemctl status vnstat. If the interface is missing, add it with sudo vnstat -i eth0 --add.

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Why are vnStat’s numbers different from my VPS panel?

They’re measured in different places and may use different units (vnStat uses GiB/TiB by default, base 1024) and different month boundaries. Use the panel for your plan’s allowance.

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How do I see bandwidth per process?

iftop works per connection, not per program. Match its ports to programs with ss -tunp. Tools such as nethogs show traffic per process directly.

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Does vnStat slow down the server?

No noticeable amount. It reads the kernel’s interface counters at intervals rather than capturing packets.

VPS and dedicated server guides

Every guide in this section.

VPS traffic and bandwidth

Traffic history in the panel.

Test speed with iperf3

Measure maximum throughput.

Monitor resources with htop

CPU, memory and processes.

Set up Netdata

Dashboards for network and more.
Checked against the official vnStat manual and usage guide and the Fedora/EPEL package listings for vnStat, iftop and nload on 4 November 2026; commands tested on Ubuntu 24.04 LTS (vnStat 2.12, iftop 1.0pre4, nload 0.7.4). Commands can differ on other distributions or releases.

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Need Extra Help?

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Last Updated: November 2026