I'm at work. Currently, we're having some fierce networking problems and every website I try to open throws an error similar to Firefox can't find the server at www.google.com.. However, I can still browse StackOverflow and I am posting this, which proves that I'm not reading from cache.
How is this possible?
your network is experiencing DNS outage. SO name is still in the local DNS resolver cache.
Sounds like a DNS issue. Point your DNS at 8.8.8.8 and 8.8.4.4 and see what happens.
For this specific issue it sounds like @Franci Penov and @iftrue are right - you're having DNS issues.
On a more general level you should make sure you have some sort of connectivity in case your primary network goes down. This can be a separate connection (DSL + cable or dialup), a cell phone with a data plan and tethering, or the local coffee shop.
dig is your friend here for analysing DNS issues. If you're a Windows man like me, you can get dig for Windows from Nicholas Fong's site. (site also has basic user guide on it) - if you can't resolve it, the server's IP is 64.59.134.11 for your hosts file!
Find out the IP address of your primary DNS server then run
dig www.google.com. @ip.of.dns.server
If that yields something with
;; AUTHORITY SECTION:
com. 900 IN SOA a.gtld-servers.net. nstld.verisign-grs.com.
(or similar) in the results, then your DNS server's poorly. If you get a list of results in the ANSWER section including www.google.com, www.l.google.com and www-tmmdi.l.google.com (for example) then your DNS resolver is working and your own PC is not.
As others have said, try Google's DNS servers. Alternatively, try OpenDNS' servers: 208.67.222.222 and 208.67.220.220. Best of luck...
