Every once in a while, something happens to give an otherwise distant-seeming news item relevance. So it was for this
http://www.cnn.com/2004/TECH/ptech/02/23/schools.gobust.ap/I'm doing DSL helpdesking. I got a call from a fellow who seemed clueful. He reported that he'd changed his IP information as the ISP had requested (they're doing a network reconfiguration), and now he'd lost connectivity. He had his XP box open to the TCP/IP dialogue, he knew where all the control dialogues were, he knew the correct names for everything. He revealed that he was an instructor at a trade school, teaching 'computers'. One might be forgiven for assuming him to have a clue about networks.
We looked at all the usual suspects. He'd entered all the data correctly, and the card was answering its own pings. Nothing would return from the gateway, though. The whole thing had been working just fine until he'd made the changes. After checking and rechecking *everything* setup-related, I finally decided to make sure that the DSL modem was getting the signal that the NIC was certainly sending. We checked - there was no activity light when the gateway was being pinged. A reboot didn't help. All the cords were plugged in tight. Hard as it was to beleive, I pretty much had to conclude that the DSL modem had gone bad just when he was making his changes. It happens.
I was about two seconds away from opening a trouble ticket to get his modem replaced, when he helpfully revealed that the lights on the router had flickered. The router? Yes, he had a router in there. He'd not thought it worth mentioning, as he'd made no changes to the router. I'd ordinarily ask about something like that early on, but this guy presented himself as a computer instructor, and seemed to know what he was doing.
So... he's got static IP, a single address, and a router between the DSL modem and the single machine. Why a router for one machine? I have no idea, and didn't ask. Why did he think that it might be a good idea to put his new IP on the machine instead of the router, which (when we checked) was set up to do NAT and DHCP? Again, I didn't ask.
I showed him how to find out what the LAN IP of the router was by doing an IPCONFIG on the workstation. I was nice, and explained why that worked, and tried to explain why we needed to configure the router and not the box. I think he understood. Hopefully he'll pass that along to his students.