Tcpdump examples

Tcpdump is a great tool for analyzing networks and hunting down associated network problems.

Tcpdump command in linux destination ip and port

Tcpdump output to file

How to install tcpdump in linux

What is the first field found in the output of a tcpdump command?

How to stop tcpdump in linux

It captures packets as they go by and shows you what’s going on and coming in on your network. The output from the command displays on the STDOUT and can also be stored in a file.

Thanks to the developers, who have kept the Tcpdump as an open source project.

It is freely available on Unix and Linux systems. Windows has a ‘Microolap TCPDUMP for Windows’ variant with an associated price tag.

has a long list of options available for use.

Tcpdump command

In this article, I'll focus on core options that are frequently used.

1. Checking the Available Interfaces

To check all the available interfaces to capture on, use the ‘-D’ flag as:

This will list all the interfaces on the system including wireless and wired interfaces and others.

The same functionality can also be gained with the flag:

2. Capturing Packets for a Specific interface

Without using any option, Tcpdump will scan all the interfaces. The flag captures traffic from a specific interfa