Network Troubleshooting Part 1

Even as enterprise infrastructure is moving towards the cloud, physical terminals, clients, devices ect... need to connect to that cloud. Even with wireless networking those wireless access point still need a wired connection. So this is how i go about checking for network connectivity.

Step 1: Check the Physical Layer. If a machine is not connecting to the network. I always pull it out and look at the link state lights. If i see green or amber flashing or steady. I then know at least the machine is connecting to something on the other end. If i don't see any lights or red lights then i know the problem is somewhere in the physical layer.

Ethernet Link Lights

Often when i pull out the client box i'll look for any bad kinks in the Ethernet. It not a common occurrence but is its possible that a really bad kink has cause internal rubbing and cross talk noise or even complete failure of the twisted pairs inside the Ethernet.

Step 2: Check the network device settings. You can read more about network device settings here. There is various ways of doing this if you're on a windows based device with command line "ipconfig /all" you bring up all the relevant adapters and their current configurations. If you're on a linux based system "lfconfig" will do the same.

ipconfig output

It is important to check the site's documentation to see if the gateway is correct or if there is a possible ip address conflict. Also it very important to see if the machine is on the right VLAN. I'll talk more about VLANs and sub netting in another blog article.

Thank your for reading please keep an eye out for part 2.