How is tcpdump used in Linux?

In Linux, tcpdump is a command-line tool used for capturing and analyzing network packets. It can be used to monitor network traffic, capture and analyze specific network packets, as well as diagnose network issues.

The primary usage of tcpdump is:

1. Open the terminal window and enter the following command:
2. tcpdump is a network packet analyzer.
3. By default, tcpdump captures and displays packets on all network interfaces. If you only want to capture packets on a specific interface, you can use the following command:
4. capture network traffic on a specified interface
5. is the name of the network interface from which to capture packets, such as eth0 or wlan0.
6. To specify the number of captured packets, you can use the following command:
7. Capture a specific number of packets using tcpdump.
8. Among them, is the number of packets to be captured.
9. To save the captured data packets to a file, you can use the following command:
10. Save the output of tcpdump to a file with the specified filename.
11. Among them, is the name of the file where the data packets will be saved.
12. If you want to display detailed information about the data packet, you can use the following command:
13. verbose output option for tcpdump
14. You can use filters to capture only the data packets that meet specific conditions. For example, to capture data packets with a target IP address of 192.168.0.1, you can use the following command:
15. Capture packets that are being sent or received from the host with the IP address 192.168.0.1.

These are just some basic uses of tcpdump, it has many other options and functions that can be viewed by using the man tcpdump command for the complete documentation.