Internet won't connect to certain sites

Factual Questions
#1

This is just weird! I can’t connect to Hotmail, CNN, Google nor my work email from my home notebook. This started yesterday. I’m running Windows XP for OS, Firefox for browser and McAfee virus protection and firewall, as well as Spyware Doctor. All other sites load fine, but those listed just will not load (they all give the message that the site is taking too long to connect). All these sites worked fine at work today, yet at home I get nothing. I even tried using Internet Explorer, but get the same result. I haven’t done anything to my machine which could have started this (in other words this has happened totally out of the blue).
Any ideas?
Thanks!

#2

Hmm, we have the same problem with one particular site. My husband can’t get it, but I can on my computer. He’s on Tablet XP…don’t know if that has something to do with it. Problems with both Firefox and IE. I don’t know what XP for OS is…maybe it’s a similar issue as Tablet XP. We’ve also got McAfee security.

Well, I wish I had ideas, but you know it’s not just you. I’m going to Google now to see if I can find something.

#3

Try disabling the firewall and they antispyware software. Does that make a difference? Can you ping those sites?

#4

check your hosts file. it may contain a line which redirects you to the wrong ip address.

using notepad, open c:\WINDOWS\system32\drivers\etc\hosts (assuming you’re using windows xp). just to be safe, make a backup of the hosts file before trying any of the following.

if you see any of those sites (google.com, cnn.com, hotmail.com, your work email) with a numerical address (probably 127.0.0.1) to the left of it, erase that line and save. then restart your browser and visit that site.

#5

Yeah, DuhCow is on the right track. If you’re getting complete failures on specific sites, and from some computers and not others, the odds are that it’s DNS-related rather than firewall/antivirus/whatever.

DNS is the system that converts “Host Names” (like “www.cnn.com”) into IP Addresses (the set of four numbers you see occasionally) which is what the Internet really works on.

Two computers on the same network, one of which can resolve a site and one of which cannot means that they’re getting their DNS differently. Two obvious ways that can happen:

  1. The hosts file (almost every OS has one, but they’re called different things and located in slightly different places) is a set of local overrides. If you’ve got an entry in there that corresponds with the site that’s not working, remove it.

  2. The DNS server is actually different: check the TCP/IP settings and see if the server is specified differently for each computer. If you’re using “Get a DNS Server Automatically”, verify that the upstream routers are the same.

Two inobvious ways this can happen;

  1. You’re not using the same router, even though you think you are. I’m starting to see a lot of this as wireless networks increase in range, strength, and popularity - your computer just “decided” to connect to the neighbor’s wireless net rather than your own this time, and your neighbor has his DNS misconfigured.

  2. Proxy Servers - These little toys get in the way of DNS requests (and others) in order to do various things: cache sites for faster access, track where you go, redirect IP ports to other ports for convenience or security, encrypt or decrypt traffic, etc. If you’ve got one of these involved in your network, all bets are off - talk to the network admin who manages it. Note that there are a few home utilities that act as proxy servers behind the scenes – if you have “special” network software, try disabling it and see if the problem goes away.