Questions about fsockopen_PHP tutorial

Questions about fsockopen

Today when I was using fsockopen to write and send an email, I found a strange problem
Here is the code:



$fp=@fsockopen("smtp.163.com","25",$errno,$errstr);

if($fp){

echo "ok";

fclose($fp);



}else{

echo "error:".$errstr;

}

echo "
";

$fp=@fsockopen("www.163.com","80",$errno,$errstr);

if($fp){

echo "ok";

fclose($fp);



}else{

echo "error:".$errstr;

}



?>


Copy the code. The result of executing the above code on the US space is:
error:Connection refused
ok

The execution result in the home space is:
ok
ok

Because I’m a good person, I don’t dare to guess whether it’s because of the server or 163
I hope you guys can help me explain
Thank you

Let me answer