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I have been having some problems with my router last few days, and in the process of narrowing down the problem, I found that while I wasn't using my home network explicitly I was having upto 1GB of uploads per day.

This is extremely concerning, and so I have been running through my systems with monitoring tools, wireshark and bandwidth monitors etc.

After going through all the PCs with no luck I turned to my NAS.

My NAS is running ArchArm, it hosts several services including a web server, dlna server, ftp server, and a couple more things.

The web server is for my personal use and shouldn't be accessed remotely by anyone but myself, even if it was, there is nothing available there to allow anybody to use so much bandwith without logging in (which only i have access to).

What I'd like to do is run a tool on this box to monitor outgoing traffic by process or otherwise to help me narrow down what exactly the problem is.

The box is headless and accessed by SSH so command line tools are required.


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up vote 2 down vote accepted

These 3 simple tools should help.

tcpdump a simple as it comes, you can quickly view all connections i.e. tcpdump port 80 will show you all packets coming via http.

iptraf in console "TUI" pretty easy to use and gives a good overview of top traffic, by no. packets bandwidth etc.

netstat use netstat -p to view running programs and their port connections, used -n if yor dns lookups are slow.

And extending on this, tcpdump can be used to create a packet cap file, using -w file.pcap, you can then load this into wireshark for more indepth analysis.

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Thank you, netstat which I installed as part of net-tools with pacman got me sorted. iptraf with it's TUI also provides fantastic information in an easy to use interface. I highly recommend the tools given in this answer as they had me problem solved in minutes. – Hamid Dec 2 '11 at 14:48
This explains filter pretty well:… – Oneiroi Dec 2 '11 at 14:48

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