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1. Check the physical and data link layers first
   1. Check the computer's power and cabling
   2. Check the network cabling and verify the link-light is reporting the correct status
   3. Verify the computer can talk to the network card and the network's default gateway using PING.
2. Check the network layer after checking the physical and data link layers first.
   1. WINDOWS
      1. At the MS-DOS prompt type:
         ipconfig /all
         
      2. If there is no IP address, the computer cannot talk to the DHCP server or has no IP address assigned.
      3. If the IP address of the default gateway is wrong, you won't be able to talk to anything that isn't on the local LAN.
      4. If the mask is wrong, you won't be able to talk to some of the computers on your network.
      5. Verify there is a Default Gateway address
      6. Verify there are DNS servers listed
   2. UNIX
      1. At the prompt, type:
         ifconfig -a
         
      2. If you see no IP address in the output, your computer has not learned one.
         1. Your computer is not configured for DHCP (this is the default on Solaris and most Linux systems)
         2. Your computer's network card cannot connect to the network.
      3. Verify the subnet mask is correct
      4. Verify there is a Default Gateway address
      5. Verify there are DNS servers listed
3. Ping the local loopback address 127.0.0.1. This verifies your hardware is working.
4. Ping your own IP address (from ifconfig or ipconfig). This verifies your network stack is working.
5. Ping the default Gateway IP address. This verifies you have LAN connectivity
6. Ping a destination by name. If this fails, try pinging the website by IP address. This verifies you can connect to hosts outside your LAN.
7. Run a traceroute to your destination.
   1. If the traceroute completes, the destination is reachable.
   2. If the traceroute fails:
      1. You May have a Routing Problem
      2. You May have a Firewall/Access List problem

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