Tcpdump: verbose output suppressed, use -v or -vv for full protocol decode The command screen will scroll up until you interrupt and when we execute the tcpdump command it will captures from all the interfaces, however with -i switch only capture from the desired interface. Once the tcpdump tool is installed on your system, you can continue to browse the following commands with their examples. Getting Started with tcpdump Command Examples Many Linux distributions already shipped with the tcpdump tool, if in case you don’t have it on a system, you can install it using either of the following commands. It saves the file in a pcap format, that can be viewed by tcpdump command or an open-source GUI-based tool called Wireshark (Network Protocol Analyzer) that reads tcpdump pcap format files. tcpdump also gives us an option to save captured packets in a file for future analysis. It is available under most of the Linux/Unix-based operating systems. Tcpdump is a most powerful and widely used command-line packets sniffer or package analyzer tool which is used to capture or filter TCP/IP packets that are received or transferred over a network on a specific interface. Here, we are going to show you how to install tcpdump and then we discuss and cover some useful commands with their practical examples. This is our another ongoing series of packet sniffer tool called tcpdump.

In our previous article, we have seen 20 Netstat Commands (netstat now replaced by ss command) to monitor or manage a Linux network.

Packet analyzer