Command-line Utilities

netstat

A TCP/IP utility that shows the status of each active connection.

tcpdump

A command-line protocol analyzer. Administrators use it to capture packets.

netcat

A network utility program that reads from and writes to network connections.

ipconfig /renew

Assigns a new IP address

ipconfig (Windows)/ip/ifconfig (Linux)

Command-line tools to manipulate the network interfaces on a system. Ability to list the interfaces and connection parameters, alter parameters, and refresh/renew connections.

nslookup/dig

Examines a DNS query for a specific address. nslookup works on Windows, dig works on Linux.

traceroute

Linux tool for viewing the path the packet takes.

netstat -at

Lists all active TCP connections

netstat -an

Lists all active UDP connections

netstat -a

Lists all active connections and listening ports

ipconfig /release

Releases current IP configuration

eth_addr

Specifies a physical (MAC) address in the arp

tracert

Windows command for tracing the route that packets take over the network. Provides a list of the hosts, switches, and routers. Uses ICMP if blocked.