Learning by Doing: CISCO Certified Network ... - SCN Research

4. The first step in troubleshooting is testing layer 1 and working our way up the
OSI model. Check the cabling. Be certain the LED on the NIC’s is lit up.
You can also do a visual verification on the cable to be certain you are using
the correct one.
5. First we can test the functionality of the NIC (layers 1-2) and the computer for
its ability to communicate with networking. We can do this by using ping to
any address on the 127.0.0.1-127.255.255.254 network. This is called the
“loopback adapter network.” So I pick an IP address from the 127 network
and ping it. You should see something like this if everything is fine:
C:\WINDOWS\Desktop>ping 127.127.127.127
Pinging 127.127.127.127 with 32 bytes of data:
Reply from 127.127.127.127: bytes=32 time
6. Next we can test our basic network connection between the two computers
using ping (layer 3). If my workstation used 192.168.1.1 and the other one
used 192.168.1.2 then I would ping 192.168.1.2 to test connectivity. If you
cannot ping the other workstation then check the IP addresses and masks on
each workstation. When all else fails reboot the workstations too.
C:\WINDOWS\Desktop>ping 192.168.1.2
Pinging 192.168.1.2 with 32 bytes of data:
Reply from 192.168.1.2: bytes=32 time
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