Those urls of yours don't work even in browser, why should they magically work in PHP?? (is - valid in DNS anyway?)

The urls are as an example, http://emdeeuk.deviantart.com/ does work.
The url that identified the problem is: http://mark-.deviantart.com/
A hyphen is valid in DNS.

Please refer to RFC833 Appendix 1.

Hyphens may not appear at the start or end of a <label>.

gethostbyname() (Used by the network streams code among other parts of PHP) treats this correctly according to RFC specification.  Your browser is simply more forgiving.

If this is the case it does not explain why it works on two machines(installed by me)and not on two otheres (installed by my hosting company).

Btw, could you post a link to the RFD you are quoting from. I searched on Google and found an RFC entitled "Who talks TCP?"

Thanks

It should be RFC883 (page 56) not RFC833.
http://www.faqs.org/rfcs/rfc883.html

"The labels must follow the rules for ARPANET host names.  They must start with a letter, end with a letter or digit, and have as interior characters only letters, digits, and hyphen."

Thanks Magnus.

This does explain possible behaviour but doesn't explain why 2 Windows PHP installs work fine but 2 Linux PHP installs (as installed by my hosting company) do not.

This seems to imply that file_get_contents() doesn't validate the DNS compliance of the arguement.

Also referring to the previously note from Pollita, as forgiving as the browser maybe the DNS servers involved in the lookup of http://mark-.deviantart.com are the ones that are dealing with this more so from what I know.
The deviantart.com DNS server software also seems to be forgiving, not just of look ups of this kind but of creating new record of this kind too, as the DNS entry would have been created when the user mark- signed up his account with Deviantart.com

"gethostbyname() (Used by the network streams code among other parts of PHP) treats this correctly according to RFC specification."

I can see this statement being inobvious.  I mean the gehostbyname() function defined by the host systems standard C library.  You assumption that PHP's network code does not attempt to validate the hostname before passing it on to the the system for resolution.  It works on some systems because on those systems the value is encoded into a DNS packet and sent to the DNS server unmangled.  On other systems, a validation check is performed first and if it doesn't pass, then it doesn't bother waiting for a network round trip, instead simply returning a failure.

Thank you Pollita. That's a lot clearer.
Do you have any suggestions for a work around for this issue?

I have an ugly solution, it's a very rudimentary HTTP/1.0 client which relies on the fact that deviantart.com uses a wildcard to direct *.deviantart.com to the same IP address.

It also relies on the fact that they're not doing any kind of 3xx redirection (at least as far as I could tell).  I wouldn't be surprised if you need to do some work on this function to make it work *well* for you.

function http_get_contents($url) {
  $resource = parse_url($url);

  $ip = gethostbyname('dummy.deviantart.com');
  $sock = fsockopen($ip, 80);
  if (!$sock) return false;

  fwrite($sock, "GET {$resource['path']}?{$resource['query']} HTTP/1.0\r\n");
  fwrite($sock, "Host: {$resource['host']}\r\n");
  fwrite($sock, "Connection: close\r\n\r\n");

  $response = fgets($sock, 8192);
  if (substr($response, 0, 3) != 200) return '';

  /* Skip headers */
  while (trim(fgets($sock, 8192)));

  $ret = '';
  while (!feof($sock)) {
    $ret .= fgets($sock, 8192);
  }

  return $ret;
}


That's PHP4/5 compliant.  If you're only worried about PHP5 compatability you can do:

$context = stream_context_create(array('http'=>array('proxy'=>'tcp://dummy.deviantart.com')));

$data = file_get_context($url, false, $context);

Which does *essentially* the same thing, but since it's a proper http wrapper takes care of the 3xx and other shortcommings of the userspace version I gave you above.

Correction:
$context = stream_context_create(array('http'=>array('proxy'=>'tcp://dummy.deviantart.com:80')));

Forgot the port number :)

Thank you for all your help, I'll try this at the weekend most likely.