Networks need fixing. Let us help you.Networks need fixing. Let us help you.
Network Administration Programs
ping - Personal InterNetwork Groper. The tool will tell you whether or not a host is reachable on the network.
Telnet - 'Teletype network' goes way back to 1969. Not very secure, but damn, is it useful. This will open a remote terminal session on a host (router, switch, firewall, server, etc.) using TCP.
TFTP - Trivial File Transfer Protocol. A file transfer protocol using UDP. SAY WHAAAA?! Yes, I use it very often to this day. SolarWinds makes a nice server for Windows.
SSH - Secure SHell is used to create a remote or local shell to a terminal. I like PuTTY in Windows, as it supports serial, telnet, and ssh in one program.
traceroute / tracert - A tool used to trace a route to a destination. The methodology used to do so involves sending ICMP packets to each 'hop' or router along the path to the destination. This often (depending on the kindness of operators of networks along your path) will give you 'breadcrumbs' at each router along your path.
arp - A command line tool that uses Address Resolution Protocol (see below) to display the MAC Address/IP Address table of connected devices. All OSs have this. - Thank you Mr. Troup!!! How could I forget this critical tool?!?! Takes one to know one?
netstat - Tool to show what your current environment is connected to on the network. netstat is built into most operating systems.
ntop - command line tool to show you the top used network resources in your environment. The creator has gone above just having a command line tool these days and has wrapped a webpage and analysis package around the tool. Worth checking out.
ps - 'Process Status' command line tool to show you which processes are running in your environment.
lsof - 'List Open Files' command line tool to show you which files are actively open in your environment.
nmap - Multifunctional internetwork host identification and services discovery tool
Wireshark - Want to 'hear what's on the wire?' Packet sniffer and analyzer that can be used to generate and inspect packet capture files (.pcap). It can be used on any network interface.
http://www.subnet-calculator.com - The OG site is still around!!! Remember classful networks? Neither do I, but they are here as well as classless (CIDR) network calculations that all network administrators and engineers should be doing!