PHP ftp_connect（）始终返回false，但首先使用的ftp服务器除外。

Question

The problem is ..
I just used ftp_connect() for the first time on my server

<?php
$ftp_connect = ftp_connect('ftp.server.com') or die('<b>FTP Connection Error ...</b>');
$login_result = ftp_login($ftp_connect, 'ftp_username','ftp_password') or die('<b>FTP Login Error ...Check Your UserName and Password</b>');
ftp_pasv($ftp_connect,true);    
?>

It worked fine and returned true.Every thing works fine with that ftp server (ftp.server.com)

Then next time I used the same server and everything was fine...BUT when I tried with another server (say: ftp.server2.com) it returned false,ie host not found ..!! I tried with all my friends ftp servers and nothing could connect except that one(ftp.server.com) what's actually going on ... why is this happening and how can I solve this ... right now i can't connect any ftp server (except my ftp.server.com) .... Thanx in advance ...

And The above thing works fine on my pc (IIS,PHP 5.3.8)

Updated : ahhh ....... figured out the problem .... but didn't find a solution.!!!! the server (here: ftp.server.com) has the same IP which the host server, where the above php is hosted - has.... and soo the ftp_connect() worked on it.... reason is both the servers ftp and http host are from same web hosting provider...

Now its clear, (I think) that firewall is the main reason for all the problem .... how to fix that firewall...?? plz help.... Thanx again..

Answer 1

You are not specifying a port number. PHP's ftp_connect() will use 21 as the default port number if you don't specify one. This script may have worked for the first server because it was running on port 21, but the other servers may be failing because they're running on different ports. Ask your friend(s) what port they're using, or use something like nmap to find it yourself.