ifconfig, route and ipconfig
- A host’s network configuration includes its IP addresses and gateway.
- On Unix, use the route and ifconfig commands to view the system’s network configuration.
- Windows systems put all of these in the ==ifconfig== command.
grep and findstr
- The ==grep== (Unix) and findstr (Windows) commands let you search for a specific string within a pile of output.
netstat
- The ==netstat== command displays a system’s established network connections, what connections the system can receive, and network statistics.
lsof
- The ==lsof== command lets you see hat processes open which files.
route
- The ==route== command both displays where the system send traffic and gives you the ability to change how the system delivers traffic.
tcpdump
- The tcpdump command displays traffic to and from a server, even when the server rejects that traffic.
netcat
- The netcat program lets you listen to the network on a specific port, and lets you send arbitrary network traffic.
traceroute
- The traceroute program (tracert in Windows) shows you the route that traffic takes and where these links break.
host and nslookup
- The host (Unix) and nslookup (Windows) commands let you peek at the Domain Name Service, which maps host names to IP addresses.