This post contains various commands that may come in useful when utilizing tcpdump. This article will be expanded upon as time goes on.


Basic Usage

Run tcpdump to collect traffic:
sudo tcpdump -i <interface>

Run tcpdump with verbosity:
sudo tcpdump -i <interface> -v

Disable DNS Conversation:
sudo tcpdump -i <interface> -n

Quieter output:
sudo tcpdump -i <interface> -q

Specify the number of packets to capture:
sudo tcpdump -i <interface> -c 100


Applying Filters

Filter based on ICMP requests:
sudo tcpdump -i <interface> icmp

Filter based on IP or hostname:
sudo tcpdump -i <interface> host <hostname>

Filter based on specific source/destination address:
sudo tcpdump -i <interface> src 10.0.0.1 and dst 10.0.0.2

Rather than filter based on source/destination, you can use Grep:
sudo tcpdump -i <interface> | grep <ipAddr>


Saving / Reading Output

To save output to a text file:
sudo tcpdump -i <interface> -w output_file.txt

To read output from a text file:
sudo tcpdump -i <interface> -r output_file.txt