PHP curl modifies website request headers

Example, php curl modifies website request headers, including useragent, header information, etc.

Code:

for ($i = 0; $i < 5; $i++) {
 task();
}
 //Modify the access request header
function task() {
 $url = "http://www.xxx.com/?fromuid=272539";
 $ip = "100.100.".rand(1, 255)." .".rand(1, 255);
 $headers = array("X-FORWARDED-FOR:$ip");

 $curl = curl_init($url);
 curl_setopt($curl, CURLOPT_HTTPHEADER, $headers) ;
 curl_setopt($curl, CURLOPT_RETURNTRANSFER, 1);
 curl_setopt($curl, CURLOPT_USERAGENT, "Mozilla/4.0");
 $src = curl_exec($curl);
 curl_close($curl);
}
?>