Connectivity Tools

These are the first tools you'll reach for when checking if a network or host is working

• ping

  send small packets to a host and measure response time. Perfect for checking if a server is up

  ping google.com

• traceroute

  Trace the path packets take to a destination. Useful for spotting where delays or drops occur

  traceroute google.com

• mtr

  An improved mix of ping and traceroute — shows real-time routes and packet loss in a single view

  mtr google.com

Moving Files and Data

Downloading files and testing servers is part of everyday Linux networking

• curl

  Fetch data from a server using many protocols (HTTP, HTTPS, FTP). Great for testing APIs or web endpoints

  curl https://example.com
  curl -I https://example.com   # Fetch only headers

• rsync

  Efficiently synchronize files and directories between systems. Only transfers differences, making it faster than plain copy

  rsync -avz source/ user@remote:/path/to/destination/
  rsync -avz user@remote:/path/to/source/ destination/

• wget

  Download files from the internet. Can handle entire websites, recursive downloads, and resuming

  wget https://example.com/file.zip
  wget -c https://example.com/file.zip   # Resume download

• nc (netcat)

  The "Swiss army knife" of networking. Can transfer files, create simple servers, or open connections

  nc -vz example.com 80      # Test if port 80 is open
  nc -l -p 1234 > file.txt   # Listen and receive a file

Exploring Your Own Network

• ifconfig

  View or configure network interfaces (IP addresses, MAC addresses, etc.)

  ifconfig
  ifconfig eth0 down   # Disable interface

• ip

  The modern replacement for ifconfig with more advanced control over routing and interfaces

  ip addr show
  ip route show

• netstat

  Show active connections, listening ports, and routing tables

  netstat -tuln

• ss

  A faster, more detailed replacement for netstat to check sockets and connections

  ss -tuln

• ethtool

  Inspect and tweak Ethernet interface settings (speed, duplex, driver info)

  ethtool eth0

• arp

  View and manage the ARP table — which maps IP addresses to physical MAC addresses

  arp -a

Working with DNS

When domains don’t resolve, these tools save the day

• nslookup

  Quickly check DNS records for a domain

  nslookup example.com

• dig

  More advanced than nslookup, providing detailed DNS query information

  dig example.com
  dig MX example.com   # Query mail servers

• host

  A simpler alternative to dig for quick lookups

  host example.com

• whois

  Find domain registration details like owner, registrar, and contact info

  whois example.com

Scanning and Analysis

For network exploration, testing, and troubleshooting deeper problems

• nmap

  Scan hosts and networks to find open ports and running services. Powerful for mapping out systems

  nmap example.com
  nmap -p 1-1000 example.com   # Scan specific port range

• tcpdump

  Capture packets directly from the network interface to analyze traffic in detail

  tcpdump -i eth0
  tcpdump -i eth0 port 80

• tshark

  The command-line cousin of Wireshark. Gives deep packet inspection without a graphical interface

  tshark -i eth0

• iperf

  Measure network speed and bandwidth between two hosts. Essential for performance testing

  iperf -s               # Run as server
  iperf -c server_ip     # Run as client