iftop command in Linux with Examples
Last Updated :
10 Sep, 2024
The ‘iftop’ command is a powerful network analysis tool used by system administrators to monitor real-time bandwidth usage on network interfaces. It provides a quick and detailed overview of networking activities, helping diagnose network issues by identifying which applications or processes are consuming the most bandwidth. It stands for ‘Interface TOP’ and the top is derived from the top command in Linux. It even acts as a diagnostic to ‘diagnose’ which program is causing the problem to the network.
Installing ‘iftop’ command
Installing ‘iftop’ on Linux varies slightly depending on the distribution you are using. Below are the installation steps for RedHat-based systems and Debian or Ubuntu systems:
1. For RedHat-based Linux (version 8 or below)
yum install epel-release
yum install iftop
2. For RedHat-based Linux (version 9)
sudo dnf install epel-release
sudo dnf install iftop
3. For Debian or Ubuntu Linux
sudo apt install iftop
Key Options available in `iftop` command in Linux
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Options
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Description
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iftop
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Displays basic real-time bandwidth usage of the default network interface.
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-i wlo1
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Shows real-time bandwidth details of a specific network interface named “wlo1”.
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-n -i wlo1
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Disables hostname lookup and provides bandwidth statistics for the specified interface “wlo1”.
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-N -i wlo1
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Disables the conversion of port numbers to services and presents bandwidth stats for the specified interface “wlo1”.
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-b
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Turns off the display of the bar graph representation for network traffic.
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-t
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Presents the output in a text interface format without using ncurses.
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-o source
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Sorts the output based on the source IP address of network flows.
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-o destination
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Sorts the output based on the destination IP address of network flows.
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-L 2 -i wlo1
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Specifies that only 2 lines of statistics or bandwidth usage should be printed for the interface “wlo1”.
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-h
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Displays the help section providing usage information and options for the iftop command.
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Working with iftop Command
1. To display basic bandwidth usage of the default interface.
iftop
Display Basic bandwidth usage
This command will now display all the bandwidth related stats of the default interface.
2. To display bandwidth details of a specific router
sudo iftop -i wlo1
display bandwidth deatil
This command will now display all the bandwidth related stats of the specified network interface which is wlo1.
3. To stop hostname lookup
sudo iftop -n -i wlo
To stop hostname lookup
This command will now stop the lookup of the hostname for the specified network interface which is ‘wlo1’.
4. To stop the conversion of port numbers to services.
sudo iftop -N -i wlo1
stop the conversion
This command will not convert the port number to services while printing stats for the specified network interface which is ‘wlo1’.
5 To stop the display of bar graph.
sudo iftop -b
Display a bar graph
This command will remove the bar graph of traffic from the output.
6. To display the text interface without ncurses
sudo iftop -t
Display without ncurses
This command will display the output in the text interface without ‘ncurses’.
7. To sort output by source address
sudo iftop -o source
To sort by source
This command will sort the output on the basis of the source address.
8. To sort output by destination address
sudo iftop -o destination
To sort by destination
This command will sort the output on the basis of the destination address.
9. To specify number of lines to be printed
sudo iftop -L 2 -i wlo1
To display specific number
This command will print 2 output lines of statistics or bandwidth usage and not more than 2 lines will be printed.
10. To display help
sudo iftop -h
help
This command will display the help section of the iftop command.
Conclusion
In this article we discussed ‘iftop’ command which is a valuable network analysis tool for administrators, providing real-time bandwidth usage stats and aiding in network troubleshooting. With customizable options, it offers efficient monitoring and sorting capabilities. By installing ‘iftop’ on Linux distributions, administrators can gain insights into network traffic and optimize network performance effectively.
‘iftop’ command in Linux – FAQs
What is the ‘iftop’ command used for in Linux?
The ‘iftop’ command is used for monitoring real-time bandwidth usage on network interfaces in Linux. It provides a quick overview of networking activities and helps identify which processes or applications are consuming bandwidth.
How do I install the ‘iftop’ command on RedHat-based Linux systems?
For RedHat-based Linux (version 8 or below), use:
yum install epel-release
yum install iftop
For RedHat-based Linux (version 9), use:
sudo dnf install epel-release
sudo dnf install iftop
How can I install ‘iftop’ on Debian or Ubuntu Linux?
You can install ‘iftop’ on Debian or Ubuntu by running:
sudo apt install iftop
How do I display basic bandwidth usage of the default network interface using ‘iftop’?
Simply run the command:
iftop