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    copied!<p>sorry for abusing the answer field for what should probably be a comment but I can't really think of a way to present this info properly otherwise. I honestly don't know yet how to whip them comments into any properly displayed and formatted shape. :-|</p> <p>Anyway, since your code should be working fine but for you it always retuns "everything OK" while you check for a HTTP response, it could be that your ISP is doing <a href="http://en.wikipedia.org/wiki/DNS_hijacking" rel="noreferrer">DNS-highjacking</a>, which basically is returning fake ip-address data, redirecting you to their own server, usually for monetary gains under the guise of userfriendlyness. (ISP-page that shows "this page doesn't exist" combined with ads or the offer of services such as domain registration, etc..)</p> <p>an easy way to test is just to ask for DNS data with an application like <a href="http://linux.die.net/man/1/dig" rel="noreferrer">dig</a>. A query to a properly functioning DNS server for a non-existing domain should return NXDOMAIN as its status:</p> <p>so when we check for a totally fake domain <code>notexisting.fake</code> with the following command: <code>dig A notexisting.fake.</code>, this is what it generally should give:</p> <pre><code>harald@Midians_Gate:~$ dig A notexisting.fake. ; &lt;&lt;&gt;&gt; DiG 9.7.3 &lt;&lt;&gt;&gt; A notexisting.fake. ;; global options: +cmd ;; Got answer: ;; -&gt;&gt;HEADER&lt;&lt;- opcode: QUERY, status: NXDOMAIN, id: 28725 ;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 1, ADDITIONAL: 0 ;; QUESTION SECTION: ;notexisting.fake. IN A ;; AUTHORITY SECTION: . 1780 IN SOA a.root-servers.net. nstld.verisign-grs.com. 2012061700 1800 900 604800 86400 ;; Query time: 24 msec ;; SERVER: 8.8.8.8#53(8.8.8.8) ;; WHEN: Sun Jun 17 18:05:10 2012 ;; MSG SIZE rcvd: 109 </code></pre> <p>as you can see,asking for this nonexisting domain <code>notexisting.fake.</code> returns us</p> <pre><code>;; Got answer: ;; -&gt;&gt;HEADER&lt;&lt;- opcode: QUERY, status: NXDOMAIN, id: 28725 </code></pre> <p>Whereas when we query for google.com, with <code>dig A google.com.</code></p> <pre><code>harald@Midians_Gate:~$ dig A google.com. ; &lt;&lt;&gt;&gt; DiG 9.7.3 &lt;&lt;&gt;&gt; A google.com. ;; global options: +cmd ;; Got answer: ;; -&gt;&gt;HEADER&lt;&lt;- opcode: QUERY, status: NOERROR, id: 13223 ;; flags: qr rd ra; QUERY: 1, ANSWER: 6, AUTHORITY: 0, ADDITIONAL: 0 ;; QUESTION SECTION: ;google.com. IN A ;; ANSWER SECTION: google.com. 300 IN A 74.125.132.138 google.com. 300 IN A 74.125.132.139 google.com. 300 IN A 74.125.132.101 google.com. 300 IN A 74.125.132.113 google.com. 300 IN A 74.125.132.100 google.com. 300 IN A 74.125.132.102 ;; Query time: 29 msec ;; SERVER: 8.8.8.8#53(8.8.8.8) ;; WHEN: Sun Jun 17 18:05:20 2012 ;; MSG SIZE rcvd: 124 </code></pre> <p>our query returns us the proper NOERROR</p> <pre><code>;; -&gt;&gt;HEADER&lt;&lt;- opcode: QUERY, status: NOERROR, id: 13223 ;; flags: qr rd ra; QUERY: 1, ANSWER: 6, AUTHORITY: 0, ADDITIONAL: 0 </code></pre> <p>and returns us the ip address found for the A record</p> <pre><code>;; ANSWER SECTION: google.com. 300 IN A 74.125.132.138 google.com. 300 IN A 74.125.132.139 google.com. 300 IN A 74.125.132.101 google.com. 300 IN A 74.125.132.113 google.com. 300 IN A 74.125.132.100 google.com. 300 IN A 74.125.132.102 </code></pre> <p>So if your query for the fake domain returns an ip address then you know the problem is with your DNS and your isp no doubt redirects every non-existing request to a server of their own, messing with your 'is my site up strategy' since you'll get a 200 OK status but it'll effectively be from an imposter.</p> <p>If this is the case then you can only:</p> <ul> <li>change your DNS server: use <a href="https://developers.google.com/speed/public-dns/" rel="noreferrer">Google Public DNS</a> (8.8.8.8 and 8.8.4.4) or <a href="http://www.opendns.com/" rel="noreferrer">opendns</a> (208.67.222.222 and 208.67.220.220)</li> <li>plead/complain with your isp for them to change this policy or to supply you with your own non-redirecting DNS server</li> <li>run your own private DNS server for your personal lookups if allowed on your network.</li> </ul>
 

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