How to find whats using network traffic

Solution 1:

nethogs shows network usage by process, sorted by highest usage first.

Solution 2:

You can use nethogs to exactly to that.

sudo yum -y install nethogs

To run nethogs:

sudo nethogs

To monitor your network you could also use iftop to monitor during your transfer, you'll see hosts you're communicating with. current, peak, cummulative transfer rates. You however won't be able to see which process.

sudo yum -y install iftop

If it says you don't have the permissions run it with sudo.

sudo iftop

To run iftop on a specific interface:

sudo iftop -i eth0

Solution 3:

You can use nettop, shows not only usage by process, but even which hostnames you send/receive data, and the split between TCP/UDP traffic. Additionally supports all IPv4 and IPv6 traffic (TCP/UDP only though).