Odd Connectivity Problem

I got a call from a family member tonight with a rather odd connectivity problem that I've got very few ideas for. If anyone can help, I'd much appreciate it.

He has several computers connected to a router in a home network. Up until yesterday, everything was working fine -- every PC could see the others on the network, and the internet beyond. Suddenly, and without any apparent cause, something went wrong with one machine yesterday -- it can see the rest of the network perfectly well, but it cannot reach the internet.

I went "um... winsockfix... maybe... er... something got corrupted in the router?.... um...driver corruption?... er... DNS problem maybe? (but all the PC's use the same DNS)... eh... virus?" (Actually, I think a virus is quite unlikely, since I know he's normally a safe enough user that it would pretty much take a zero-day exploit to get him.) Can anyone improve upon the incoherent, mumbling "advice" I gave him?

Cables and other obvious things have been checked?

I'll keep thinking on this one in the meantime.

Yes, cables and such were checked before I was called.

Moreover, cables and other obvious things should affect the connection to the rest of the network, not just the internet.

Aye, true, true. Must be sleepier than I thought.

Reset the router?

I didn't ask, but I don't think he'd be stupid enough not to try that first.


[Edit: He solved the problem himself. The most recent windows security update broke his Zone Alarm. (I keep telling him to get rid of ZA and get Comodo, sigh...) Anyway, the problem is solved, so this can be closed unless anyone has a use for it being open.]

Nah, it's not stupid to miss stuff like that.

I hope you don't think I'm suggesting things like this because I think you're inept or anything either. I'm just running through the checklist in my mind.

Let's see...what else...

Having something like Zone Alarm or Comodo and a router with a firewall is redundant. My Linksys has a firewall so I don't bother. If his router doesn't have a firewall, it may be $50.00 well spent if he upgrades his router to one that does.

Why? Because Windows Update has never "broken" the router's firewall.

Imo, on the computer thats having trouble

run -> cmd -> ipconfig/renew

Glad it was fixed.

There should probably be a thread about Windows Updater breaking ZA. I'll see what I can do.

/voted for close.

It's in Painbringer's latest response to the connectivity issues thread, Kat - http://www.guildwarsguru.com/forum/s...0306440&page=3

Yeah, just saw that Sno, thanks.