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Bug #24756 fsockopen not detecting closed ports
Submitted: 2003-07-22 15:36 UTC Modified: 2003-11-17 18:16 UTC
Avg. Score:4.3 ± 0.9
Reproduced:2 of 2 (100.0%)
Same Version:1 (50.0%)
Same OS:2 (100.0%)
From: nalldrin at cs dot ucsd dot edu Assigned:
Status: No Feedback Package: Sockets related
PHP Version: 4.3.3RC2-dev OS: Windows XP Pro
Private report: No CVE-ID: None
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 [2003-07-22 15:36 UTC] nalldrin at cs dot ucsd dot edu
I'm running PHP 4.3.2 on Windows XP and think I've found a bug in fsockopen().  When attempting to open a closed, non-blocked port, fsockopen() times out instead of returning immediately.  On linux, fsockopen() returns immediately instead of timing out.  I've tried the latest CVS version (php4-win32-STABLE-200307211230) and get the same problem.  Also perhaps relevant is the fact that fopen() seems to work correctly (ie, it does not time out like fsockopen).

Note: I think this is the same problem as bugs 23131, 21193, etc., but the problem does not seem to be fixed.

Here's some more info about the machine/php version I'm running:

Microsoft Windows XP Professional Version 2002 Service Pack 1
Xeon 3.06GHz

<a href=">phpinfo</a>

Reproduce code:

$hostname = 'localhost'; //use any hostname:port combo that is closed, but not blocked
$port = 81;
$errno = null;
$error_str = null;

// FSOCKOPEN does not detect closed port and waits until timeout
echo microtime() . "\n";
$fp = fsockopen( $hostname, $port, $errno, $error_str, 10);
echo microtime();

echo "\nerrno: "; var_dump($errno);
echo "error_str: "; var_dump($error_str);
echo "retval: "; var_dump($fp);
if ($fp !== false) fclose($fp);

// FOPEN seems to correctly detect closed port and returns immediately
echo microtime() . "\n";
$fp2 = fopen ("http://$hostname:$port", "r");
echo microtime();

if ($fp2 !== false) fclose($fp2);


Expected result:
The script should return immediately, saying the hostname/port is closed or something to that effect.

Actual result:
The fsockopen() call times out.

0.98491200 1058903395
<br />
<b>Warning</b>:  fsockopen(): php_hostconnect: connect failed in <b>c:\Inetpub\wwwroot\phpbug\fsockopenbug.php</b> on line <b>11</b><br />
<br />
<b>Warning</b>:  fsockopen(): unable to connect to localhost:81 in <b>c:\Inetpub\wwwroot\phpbug\fsockopenbug.php</b> on line <b>11</b><br />
0.98788000 1058903405
errno: int(10060)
error_str: string(185) "A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond."
retval: bool(false)
0.98791200 1058903405
<br />
<b>Warning</b>:  fopen(): php_hostconnect: connect failed in <b>c:\Inetpub\wwwroot\phpbug\fsockopenbug.php</b> on line <b>22</b><br />
<br />
<b>Warning</b>:  fopen(http://localhost:81): failed to open stream: Bad file descriptor in <b>c:\Inetpub\wwwroot\phpbug\fsockopenbug.php</b> on line <b>22</b><br />
0.94688200 1058903406


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 [2003-07-23 00:54 UTC]
The http:// wrapper internally calls the same connection routines as fsockopen, so I can't see how it could be behaving differently (error messages aside).

Can you explain what you mean by a closed-but-not-blocked port?
 [2003-07-23 01:06 UTC] nalldrin at cs dot ucsd dot edu
The problem isn't with fopen(); it's with fsockopen() which should be trying to create a raw tcp:// connection, not an http:// connection.  The point of comparing fsockopen with fopen was to show that somehow fopen can tell that the port is closed while fsockopen cannot (since they both need a tcp:// connection).

What I mean by "closed but not blocked" is a port that won't accept a tcp connection, but still sends out a reply to the connection attempt saying it's closed.  A blocked port would pretend it didn't see the connection attempt at all.  I'm probably muddling my terminology, but that's what I mean :).
 [2003-07-23 01:10 UTC]
*sigh* yes, fsockopen() creates a tcp connection.
the http:// wrapper uses those tcp connections to talk http.

So... you just mean a port that is not filtered but has no processes listening on it?

 [2003-07-23 14:10 UTC] nalldrin at cs dot ucsd dot edu
Yes, that's what I mean.

I wrote a more simple test case that tries to open port 9999 on  On linux the test returns immediately, as it should. But on win32, it spins until timeout.


// fsockopen spins on win32 on opening non-existant ports when it should fail

$startTime = time();
fsockopen("", 9999, $errno, $error_str, 10);
$totalTime = time() - $startTime;

if($totalTime >= 10) {
  print("Spun until timeout trying to open a closed port.  Huh?");


Content-type: text/html
X-Powered-By: PHP/4.3.2

<br />
<b>Warning</b>:  fsockopen(): php_hostconnect: connect failed in <b>C:\cygwin\home\Neil Alldrin\test.php</b> on line <b>7</b><br />
<br />
<b>Warning</b>:  fsockopen(): unable to connect to in <b>C:\cygwin\home\Neil Alldrin\test.php</b> on line <b>7</b><br />
Spun until timeout trying to open a closed port.  Huh?
 [2003-07-24 09:08 UTC]
On WinXP using latest stable snapshot from July 24th does infact stall and wait for the timeout to occur.
fsockopen("", 9999, $errno, $err_str, 10);
However, this does not appear to happen with PHP5 snapshot.
 [2003-11-17 18:16 UTC]
No feedback was provided. The bug is being suspended because
we assume that you are no longer experiencing the problem.
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