All websites reachable but suddenly not dns-ok.us

Yesterday, on two computers, no trouble visiting dns-ok.us site and the "green" image was shown. Both computers up to date on protection by Norton (IS and 360, different computers). Now, this evening, although we can visit nearly all websites, on three different computers the dns-ok.us site is unreachable. Not sure if this means we are infected. CANNOT BE.

Windows 7, direct broadband connection,Norton 360 - earlier, dns-ok.us OK. Tonight cannot reach.
Windows XP, wifi, Norton I.S. - yesterday, dns-ok.us OK. Tonight not yet rechecked.
Windows Vista, wifi, Norton 360 - yesterday, dns-ok.us OK. Tonight cannot reach.
Windows Vista, wifi, Norton 360 (a different one) - Tonight dns-ok.us cannot reach.

In addition, on one of the Vista-Norton360 machines, I just did a full scan with Norton 360 and result was clean.

We can reach any website we want on the machines, but just not the dns-ok.us site. Also, on the "a different one" Vista-N360 machine, that machine is always used clean, without any significant downloads of files, almost never used for internet, so this machine is believed to be completely clean. No software has been installed on it for about 3 years, except for Java 7U5 runtime environment update.

I am just wondering if the dns- check site is suddenly unavailable by too many people trying to check it at the last minute, or if something else has been done to it?

http://www.dns-ok.us/ works for me. Just for kicks, try typing or copy and pasting the actual IP address http://38.68.193.96 into the address bar.

FlannelBack,

I did not yet try what you suggested, but I had a chance to recheck two of the computers for the website.

The Windows 7 wired braodband connected and the Windows XP wifi connected. Early this morning, both were successful in visits to dns-ok.us and the "Green" image was displayed. Apparantly the earlier being unreachable was just temporary.

That link is dead but has a pointer to here-

http://dcwg.org/

Now, do you trust it to scan your system...:/

Don't believe it's scanning your computer Shibumi77, at least not according to this:

From http://www.dcwg.org/?page_id=381

* No Software is Downloaded! The tools do not need to to load any software on your computer to perform the check.
* No changes are performed on your computer! Nothing is changed on your computer when you use sites like http://www.dns-ok.us/.
* No scanning! The “are you infected with DNS Changer” tool does not need to scan your computer.

No internet troubles, and dns-ok.us site works again. Resolution = GREEN