Why are some websites not resolving?

0

Problem: Some big websites like homedepot.com and cbc.ca websites will not resolve. The browser just sits there and no content is shown. What could be causing this? Also get

Request timed out.

with ping.

nslookup

C:\Documents and
Settings\rwhite>nslookup homedepot.com
Server:
google-public-dns-a.google.com
Address:  8.8.8.8

DNS request timed out.
    timeout was 2 seconds. Non-authoritative answer: Name:
homedepot.com Address:  207.11.41.2

Also, the windows hosts file only has a single line:

127.0.0.1       localhost

O.O

Posted 2011-03-27T21:05:15.290

Reputation: 141

Which OS do you use if you use windows go to the command line and type "nslookup". Then you can type in your site and check if the DNS resolve the name. – René Höhle – 2011-03-27T21:10:39.203

Sounds like an issue with your ISP. – ChrisF – 2011-03-27T21:11:37.993

I guess one idea would be to try to narrow it down to whether the problem's your computer, or some glitch at your ISP (or with the modem/router). Do you have a laptop? Plug it into the same internet connection and see if it also fails to connect to these sites. If so it's not your computer settings, look at your modem/router settings. If nothing stands out, call your ISP. – CreeDorofl – 2011-03-27T21:13:37.133

@Stony - WinXP Pro – O.O – 2011-03-27T21:15:20.870

@CreeDoroftl the only access I have at the moment is with remote desktop. Already called ISP and they claim everything is fine. DSL modem has all security restrictions disabled. I've tried to use google's DNS servers but nothing changes. – O.O – 2011-03-27T21:17:17.517

Then you can try to resolve it. With the "nslookup" tool. Other way try for example the google DNS server "8.8.8.8". @subt13 – René Höhle – 2011-03-27T21:17:48.640

@Stony - Yep, I updated my q. – O.O – 2011-03-27T21:19:23.863

Could be some malware which is redirecting DNS requests to stop you getting at sites to fix the problem. There are other questions here on Super User about that. – ChrisF – 2011-03-27T21:33:00.423

@ChrisF - I thought it might be that too, but if it is trying to redirect, it isn't resolving the malware site either :P – O.O – 2011-03-27T21:41:08.207

Not all malware redirects you to their site. Some just stops you accessing other sites so you can't get rid of it. – ChrisF – 2011-03-27T21:43:03.783

@ChrisF - I see, but could the malware affect the simple ping program or the nslookup program? – O.O – 2011-03-27T21:49:31.027

Yes - if you are using the domain name - ping homedepot.com - it still has to use the DNS to change the name into an IP address. – ChrisF – 2011-03-27T21:51:24.777

@subt13 make sure you don't have any proxy server settings set up in internet explorer. That setting also affects how other programs connect to the internet. Malware often changes that setting. – James T – 2011-03-27T21:52:08.847

@James - Thanks, but both IE and FF are set to No Proxy – O.O – 2011-03-27T22:14:39.983

Did you switch to Google's DNS servers manually? Is there some reason you're not using your ISP's local DNS servers? – goblinbox – 2011-03-28T00:15:47.270

@goblinbox - I switched to them after I had this issue I'm trying to solve. – O.O – 2011-03-28T14:18:57.287

If you're having the same results with two different DNS servers, I'd then begin suspect your DSL modem just as @kez said earlier. Most Qwest DSL modems do function as routers. Or there may be some strange software on your computer. Had you installed anything immediately before the issues started? Also, can you provide a longer list of sites that do and don't resolve? – goblinbox – 2011-03-29T23:34:36.380

Answers

0

If I type:

ping homedepot.com

I get:

Pinging homedepot.com [207.11.41.130] with 32 bytes of data:

Request timed out.

But if I type:

ping www.homedepot.com

I get:

Pinging a472.b.akamai.net [84.53.134.200] with 32 bytes of data:

Reply from 84.53.134.200: bytes=32 time=42ms TTL=58

Notice the difference. The subdomain www.homedepot.com resolves straight away, but not homedepot.com. However, if I type homedepot.com into a browser it takes me to the site at www.homedepot.com.

The site could well be configured to reject ping and other requests as a security measure.

cbc.com returns similar results.

ChrisF

Posted 2011-03-27T21:05:15.290

Reputation: 39 650

ya, you're right I can ping them now that I changed, the webpage still doesn't resolve. – O.O – 2011-03-27T21:59:05.687

@subt13 - which browser are you using? Have you tried clearing the cache, checking the proxy settings etc, or indeed using a different browser. – ChrisF – 2011-03-27T22:00:24.550

firefox 3.5.11 and IE 7. Yep, tried that. – O.O – 2011-03-27T22:02:10.363

0

The inability to browse certain websites is a classic symptom of your MTU setting on your router being too high. It might not be what is causing the problems in your case, but it is definitely worth looking into if all else fails.

MTU is discussed in great detail on kitz.co.uk along with a tool called DrTCP which you can download to tweak the settings on your computer.

DrTCP will attempt to calculate out the best MTU setting for you. You would then have to hop onto your router's web interface and change the setting.

Kez

Posted 2011-03-27T21:05:15.290

Reputation: 15 359

I have no router. I have a crappy qwest modem :P – O.O – 2011-03-27T22:04:11.050

Hmmm if you don't have a web interface or telnet ability with instructions to use it, try running the test at dslreports.com/tweaks and try the DrTCP tool on your computer anyway. – Kez – 2011-03-27T22:24:43.070