Network tech support brain-twister

February 10, 2006 8:02 AM

Riddle me this: there are two Windows XP computers (desktop and laptop) on the same Internet connection, behind the same router, connecting wirelessly to it. The laptop often (but not every time) takes a really long time (30 seconds+) to send email and connect to certain websites. The desktop never has this problem. What's going on?

Here are a few things I've checked:

- Wireless signal strength is fine
- When the laptop is taking a long time connecting to sites others work fine at the same time
- Scanned for spyware/viruses with MS Anti-Spyware and Spybot Search & Destroy (clean)
- Has the web problem in three different web browsers (IE6, Netscape 7, Firefox 1.5)
- Has the email problem in both Netscape mail and Outlook Express
- Windows firewall is disabled
- Disabled Javascript/Java/Cookies in Firefox
- Disabled any virus checkers/resident anti-spyware
- Cleared everything out of the tray
- Checked network setup, it's identical to the desktop

One of the sites that's reliably slow (though again, not every time) on the laptop but not on the desktop is tremblant.ca.

All I can think of at this point is that something's been fundamentally hosed and the laptop needs a full XP reinstall. But I'd love to know what the heck's going on if anyone knows.

posted by frenetic to computers & internet (10 comments total)

It could be that the laptop is turning off the wireless card to save power and the delay is happening when it brings it back up. Does the delay happen when the laptop is plugged into mains power as well, or only on battery? You can check the card in your device manager - right-click on the card entry, properties, go to the power management tab.
posted by Dipsomaniac at 8:10 AM on February 10, 2006

The laptop's always plugged into the wall and the laptop power is fine. And it'll do it as I'm sitting there hitting reload back to back so I don't think it's idling or anything.
posted by frenetic at 8:53 AM on February 10, 2006

I know you said network setup is the identical as the desktop. This did include the dns entries right? If I was trying to guess at the problem that would be the first thing I would look at because this is happening with some websites and not others.
posted by Gilgad at 9:00 AM on February 10, 2006

Even though it's plugged in, on many laptops the wireless card is set by default to be turned off if not used for a period of time. I'd try bringing up a command prompt and running a ping with the -t option and pinging the wireless access point or gateway IP address. If you don't begin to receive replies in the 1st couple of echo requests I would look further into the possibility that your laptop is automatically turning off the wireless card when not in use.
posted by white_devil at 9:59 AM on February 10, 2006

Gilgad: DNS is what I originally suspected as well. But the TCP/IP settings on both machines are set to obtain the IP and DNS servers automatically. Could they be getting detected incorrectly?
posted by frenetic at 10:33 AM on February 10, 2006

You could grab a copy of Ethereal, record a log snippet on your ethernet port while the machine is having it's issues, and post the log where we can look at it.

Wouldn't take much longer than waiting for the next 36 wild-eyed guesses to roll in here....
posted by paulsc at 11:09 AM on February 10, 2006

I have a similar problem with my network at home. I have multiple macs, all with the same settings but some are wonky when it comes to sending / recieving(?) network packets. For me, I suspect (but can't prove) it's a time of day thing: I do more computing in the evenings on the couch at home... so I use the laptop. Perhaps you also have patterns of usage that might explain things?
posted by zpousman at 11:32 AM on February 10, 2006

Might be worth making sure you have the latest drivers for your NW card: ones from the manufacturer's website, not the autmatically installed MS ones. I've seen plenty of machines on a go-slow because of bad drivers.
posted by qwerty155 at 12:13 PM on February 10, 2006

I too think this sounds DNS related. And it could be occuring even if both computers are configured to use the same DNS servers of your ISP. One possible scenario is that one of the two computers is caching the DNS responses correctly while the other is not, and your ISP's servers are sometimes slow to respond. Check that the "DNS Cache" service is running on both PCs. Since it seems like this happens regularly enough that you can reproduce it, the next time it happens try running "ipconfig /displaydns" on both machines and see if one of them has the name in its cache and the other doesn't. Also try "nslookup example.com" from the machine that sees the failure. If nslookup succeeds but the browser still can't load the page then that more or less eliminates DNS from the mix.

You might also consider using a different set of DNS servers or even running your own. You don't need anything fancy like a linux machine -- there are bind9 binaries available for win32 on the ISC site. I find that running my own caching resolver insulates me a great deal from the crapulence of my ISP's overloaded DNS servers. More than once in the past I've need news articles about Comcast's "outages" which affect a large area that turn out to just be their shitty DNS servers that are overloaded -- smooth sailing for me, though.
posted by Rhomboid at 6:06 PM on February 10, 2006

Cranking up the power on the wireless card seemed to work. Why it would fail only on some sites and not others is beyond me, but there you have it.
posted by frenetic at 9:19 AM on March 13, 2006