Introduction

Netstat is a command-line network utility that displays network connections for Transmission Control Protocol (TCP), routing tables, and a number of network interface and network protocol statistics.

The following cheat sheet goes over a few common netstat commands.

# To view which users/processes are listening to which ports:

sudo netstat -lnptu

# To view routing table (use -n flag to disable DNS lookups):

netstat -r

# Which process is listening to port <port>

netstat -pln | grep <port> | awk ‘{print $NF}’

# Example output: 1507/python

# Fast display of ipv4 tcp listening programs

sudo netstat -vtlnp –listening -4

# Displays network-related information such as open connections, open socket ports, etc.

# List all ports:

netstat -a

# List all listening ports:

netstat -l

# List listening TCP ports:

netstat -t

# Display PID and program names:

netstat -p

# List information continuously:

netstat -c

# List routes and do not resolve IP to hostname:

netstat -rn

# List listening TCP and UDP ports (+ user and process if you’re root):

netstat -lepunt

# Print the routing table:

netstat -nr