ping

“are these computers even connected?”

curl

make any HTTP request you want

httpie

like curl but easier (“http get”)

wget

download files

tc

on a linux router, slow down your brother’s internet (and much more)

dig/nslookup

what’s the IP for that domain? (DNS query)

whois

is this domain registered?

ssh

secure shell 💙

scp

copy files over a SSH connection

rsync

copy only changed files (works over SSH)

ngrep

grep for your network

tcpdump

“show me all packets on Port 80!”

wireshark

look at those packets in a GUI

tshark

command line super powerful packet analysis

tcpflow

capture & assemble TCP streams

ifconfig

“what’s my IP address?”

route

view & change the route table

ip

replaces ifconfig, route, and more!

arp

see your ARP table

mitmproxy

spy on SSL connections your programs are making

nmap

in ur network scanning ur ports

zenmap

GUI for nmap

p0f

identify OS of hosts connecting to you

openvpn

a VPN

wireguard

a newer VPN

nc

netcat! make TCP connections manually

socat

proxy a TCP socket to a unix domain socket + LOTS MORE

telnet

like SSH but insecure

ftp/sftp

copy files. sftp does it over SSH.

netstat/ss/sof/fuser

“what ports are servers using?”

iptables

set up firewalls and NAT!

nftables

new version of iptables

hping3

construct any TCP packet you want

traceroute/mtr

what servers are on the way to that server?

tcptraceroute

Use top packets instead of icmp to traceroute

ethtool

manage physical Ethernet connections + network cards.

iw/iwconfig

manage wireless network settings (see speed/frequency!)

sysctl

configure Linux kernel’s network stack

openssl

do literally anything with SSL certificates.

stunnel

make a SSL proxy server for an insecure server

iptraf/nethogs/iftop/ntop

see what’s using bandwidth

ab/nload/perf

benchmarking tools

python 3 -m http.server

serve files from a directory

ipcalc

easily see what 13.21.2.³⁄₂₅ means

nsenter

enter a container process’s network namespace