Of all the linux tools I’ve came across, this one might be one of the most important. Today I am going to tell you about a tool called “iftop”. This program is great as viewing bandwidth usage per connection. It can be a great tool to mitigate DDOS attacks (If you are watching) and see top bandwidth users for a particular server. Once you install iftop, just run it from command line iftop -i eth0 (replace eth0 with your adapter). You can disable DNS lookups as well with the -n option. You can also toggle what you want to view for by pressing “T”. By pressing “T” you can view sent and received as an option. You can also pause by hitting “Shift P” and scroll with “J” and “K”. You can also filter with “f” and sort subnets with “F” and also toggle port numbers with just “P” Pretty nice tool! For example you could use the command below.
[root@localhost]# iftop -i eth0