I sat down at my computer recently to finish writing my newsletter, only to find the hated words "Not connected."
Windows 7 was informing me that I had no network connection. Not just no Internet access, but not even access to the other computers on my home network. This was a horrible morning.
Everything worked fine last night when I went to bed. It was time to put on my Debugging Hat…
My first step was to reboot my cable modem and my router. The process was easy and seemed to be fine. Unplug the power to the cable modem; unplug the power to the router; plug in the power to the cable modem; wait for the cable modem to download it’s configuration data from the cable Internet service provider and stabilize it’s lights, plug in the power to the router so it can make its connection to the cable modem and to the other computers and the Gigabit Ethernet switch connected to it.
But, it didn’t solve the problem…
My next "debugging" step was to call my son to see if he had experienced any problems the previous night, or had made any wiring changes. He had been playing World of Warcraft when I went to bed. No hints from this, though, as he had not had any problems and had not made any changes to the router, modem, or network wiring.
Another dead end…
Now, it was getting interesting and I had an Ace up my sleeve — actually an Acer…
I pulled my Acer ultralight notebook out of my rolling carry bag.
I remembered that my router was a wireless router, as well as providing wired Gigabit Ethernet connections. I wondered if the wireless connection would work. I powered on the notebook and immediately got an 802.11n wireless connection. I could use Firefox to get to web sites, so that let me know that the router was at least working wirelessly.
Does it work with Ethernet cables? I plugged the notebook into an Ethernet cable coming from the second Gigabit switch — no luck.
So, I disconnected the cable from the switch and plugged it directly into the router. Voilá! A network connection and an Internet connection via the wired cable. Just to make sure, I turned off the notebook’s wireless card. Yes, I still have access to the Internet. Yea!
Why did it happen? Who knows? Everything worked fine last night; then, at some time during the night, the 8-port Gigabit router failed, taking down network access for everything connected to it, including another Gigabit router, two networked printers (one black & white and one color), and multiple computers.
Continue reading in Debugging and Solving the Network Is Down, No Internet Access Problem