PHP套接字错误：socket_connect（）：主机查找失败[-10001]：/usr/local/nginx/html/test1.php中的未知主机

I write a simple socket server on one computer:

<?php
$socket = socket_create(AF_INET, SOCK_STREAM, SOL_TCP);
if(!socket_bind($socket, 'localhost', 52222)){
    exit(socket_strerror(socket_last_error($socket)));
}
if(!socket_listen($socket)){
    exit(socket_strerror(socket_last_error($socket)));
}
$conn = socket_accept($socket);
if(!$conn){
    exit(socket_strerror(socket_last_error($socket)));
}


socket_write($conn, "250 HAHA
");

It listens on 52222, and I use netstat -tnlp can find it listens on 52222 successfully.

On another computer I write a simple client,

<?php
$socket = socket_create(AF_INET, SOCK_STREAM, SOL_TCP);
if(socket_connect($socket, 'http://192.168.161.133', 52222)){
    exit(socket_strerror($socket_last_error($socket)));
}

but when I run it, an error happened

PHP Warning:  socket_connect(): Host lookup failed [-10001]: Unknown host in /usr/local/nginx/html/test1.php on line 3

I had close firewall on both computer.