Dell + Vista + DSL = WTF

September 15, 2007 10:19 AM

Why can I only browse certain web-sites with my Dell PC (Windows Vista Home Premium) and my DSL High Speed Internet (Bell Sympatico)?

I received my brand new Dell PC yesterday. This is a desktop computer running Windows Vista Home Premium. After setting up the OS and exploring a little, I configured my internet connection. I have a DSL connection (Bell Sympatico High speed) with a "Speedstream 5200" modem. To my delight, the connection was a breeze to install, and I was surfing the web in a few minutes. However, after a few minutes of browsing, I found that certain web-sites are inaccessible. For example, it's impossible for me to go to espn.com or microsoft.com (these are just examples, there are plenty of other sites I can't access). When I try accessing these sites, the progress bar stays around the halfway point, and the status bar reads something like "Waiting for reply from http://microsoft.com". The page is never displayed. I'm able to browse other sites without a problem (MeFi for example). The ratio of browsable to unbrowsable is about 60:40. The behavior is the same in IE and Firefox.

I called the Dell Tech Support line, and after 3 hours of troubleshooting to no avail, the person gave up and told me to contact my ISP (Sympatico). I contacted Sympatico, and after several more hours of troubleshooting to no avail, the person told me to contact Dell. So now I'm stuck in an infinite loop. FYI, here are some of the things that the Dell/Sympatico tech support already made me do: uninstalling the anti-virus, disabling the firewall, changing the security settings in IE, disabling applications, re-installing Windows, running Windows in safe-mode, executing the "flushdns" command, executing the "netsh int ip reset" command.

If I connect my modem to my previous PC running Windows XP, everything is 100% fine (I can browse any web-site).

After all this and trying to search the web for solutions (I am using my previous Windows XP PC now), I am out of inspiration. I don't know where to look anymore, since I don't know if the problem is with the modem, the OS, the network card, or something else. Any ideas / insight you may have are greatly appreciated. Also, please let me know if you think this question would be better suited for a particular message board. FWIW, I'm located in Ottawa, Canada.

posted by mcroy to Computers & Internet (17 answers total)

My first question would be can you ping these websites?
From the command prompt, type "ping espn.com"
The command prompt should say "Pinging espn.com [ip address]."

If that fails (IIRC, you'll get a "destination host not found" message), try pinging their actual IP addresses. I usually use DNSstuff and use the DNS Lookup under Hostname tools. If you type in espn.com, you'll get an ip address for an answer to use in your pinging. If you're able to ping the IP address, you might also be able to copy and paste it into your web browser and access the website that way (espn.com allows it).
posted by jmd82 at 10:45 AM on September 15, 2007

Have you tried restarting the modem. My modem has trouble switching between computers without a restart.
And are you using the same network cord for both computers?
posted by DJWeezy at 11:00 AM on September 15, 2007

Response by poster: I'm able to ping espn.com, but I'm NOT able to ping microsoft.com. Strangely, in a browser, they both behave the same (page never displays). Also, I'm not able to get to either of these web-sites by using the IP in the browser.
posted by mcroy at 11:07 AM on September 15, 2007

Response by poster: DJWeezy: I performed a reset on the modem, and the behavior didn't change. I also unplugged / replugged the modem, and the behavior didn't change. Yes, I'm using the same network cord for both computers.
posted by mcroy at 11:09 AM on September 15, 2007

mcroy: when you ping microsoft.com, does your computer resolve an ip address?
posted by jmd82 at 11:30 AM on September 15, 2007

Response by poster: jmd82: When I ping microsoft.com, the result is the following:

Pinging microsoft.com [207.46.232.182] with 32 bytes of data:

Request timed out.
Request timed out.
Request timed out.
Request timed out.

Ping statistics for 207.46.232.182:
Packets: Sent = 4, Received = 0, Lost = 4 (100% loss)
posted by mcroy at 12:36 PM on September 15, 2007

Is there a router anywhere in the mix?
posted by bh at 12:46 PM on September 15, 2007

Best answer: Assuming there is no router (and if there isn't, you really, really should get one), try this command:

netsh interface ipv4 show subinterfaces

If the MTU setting is over 1400, you might need to try this command:

netsh interface ipv4 set subinterface “Local Area Connection” mtu=1430 store=persistent

I don't have a Vista box handy to test these on, but the google search for 'vista mtu setting dsl' came up with this page.
posted by bh at 12:58 PM on September 15, 2007

Response by poster: bh: No, there is no router. Just one modem connected to one PC.
posted by mcroy at 12:59 PM on September 15, 2007

Best answer: My understanding is that Windows default MTU is 1500 which can throw things off. I've used used DrTCP in the past and set it around 1200-1400 with success. Not sure if it works on Vista though.
posted by jmd82 at 1:39 PM on September 15, 2007

Um, MeFi's borking my links:
http://www.dslreports.com/drtcp
posted by jmd82 at 1:41 PM on September 15, 2007

Here's what I strongly recommend you do, for investigating your problem as well as for general security: get a cheap router.

Configure the router to use your modem connection, and make sure you're not forwarding any external IPs to any machine on your local network. Then, plug both machines in and configure 'em both to surf.

In a few past cases I've found that various stupid issues like yours magically go away when you let a compatible router handle the dirty work of communicating with your modem (for authentication and the like.) With a cheap router costing around $25 at Fry's, it's hard to go wrong.
posted by davejay at 2:14 PM on September 15, 2007

Oh, and seconding dslreports; go there and use their tweak/test tools. Very helpful.
posted by davejay at 2:14 PM on September 15, 2007

Response by poster: bh and jmd82: I ran the 2 netsh commands that bh provided, and it seems to work now. The MTU was set at 1480, and changing it to 1430 did the trick. I can't thank you guys enough for your help. 6 hours of tech support didn't even come close to the help you gave me today. Thank-you very much, I hope some day I can be of help to you!
posted by mcroy at 2:16 PM on September 15, 2007

For what it's worth, I also found networking to be a bit slow when I first started using Vista. I didn't see the same issues you saw, but I found it slow overall. What helped me was to disable IPv6 for the connection I was using. I didn't need it and still don't.
posted by tcv at 6:21 PM on September 15, 2007

Sympatico requires an MTU of 1460 or less due to their sloppy configuration. It's well known enough outside the windows world. Other DSL providers support a higher MTU as they go through different routers (Bell's "BAS" boxes).

You can check the MTU with:

ping -f -l nnnn example.com

Where nnnn is the MTU size you want to test, and example.com is a known, presently working, pingable host. Of course, you can't test an MTU larger than the one you have set for the presently connection. :-)

If you use a router, you may find you need to set this setting again, and you may also need to set it on each computer that uses this link. Just FYI...

(Some popular MTU settings to try, bigger is better if it works: 1492, 1460, 1452, 1412.)
posted by shepd at 9:51 PM on September 15, 2007

Response by poster: shepd: Thanks for the information, I'll test the MTU size when I get home to see how high I can go.

It's frustrating to see that this is a known Sympatico problem, yet their tech support refuse to help customers beyond the basic "delete your cookies / reboot your pc" crap. Surely I'm not the first customer to have this problem, especially since Vista's default MTU is 1500.

Thanks again, everyone.
posted by mcroy at 4:52 AM on September 17, 2007