Description:
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When I pass a parameter of session_name()=session_id() in a url or as a header and use curl  or simplexml the connection times out. I get the following response from simplexml_load_file($url).

failed to open stream: HTTP request failed!

However, when I connect to the same url with curl on the commandline I get the expected response immediately.



Reproduce code:
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echo $data_source_url = DATAURL.'?bget=1&'.session_name().'='.session_id().'&basket_id='.clean_from_db($basket_id);
$basket_details = simplexml_load_file($data_source_url);

I also get the same when I use:
$ch=curl_init();
echo $this->URL.$this->XMLRequest.'?'.$urlstring;
curl_setopt($ch, CURLOPT_URL,$this->URL.$this->XMLRequest.'?'.$urlstring);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
$data = curl_exec($ch);
curl_close($ch);

or pass it as a more standard CURLOPT_HTTPHEADER to curl_setopt.

Expected result:
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To retrieve xml from the server.

Actual result:
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The page is called which then attempts to connect to the data url, that stalls for some time then calls the server correctly then the script eventually times out.

I've used wireshark on the machine and it's calling the url correctly and getting the expected response, as I can see the xml being passed back, but somewhere between then and actually returning, it stalls and times out.