can't get fsockopen() to work through IIS

I have PHP 5.2.6 installed under Windows Server 2003 and IIS 6.0. I cannot get fsockopen() to succeed when run through IIS. I'm using this script: <?php $host = "localhost"; $port = "110"; ?> <html> <h1>Attempting to open socket on host '<?php echo ("$host")?>' at port '<?php echo ("$port")?>'</h1> <h2> <?php $errno = 0; $errstr = "<no error reported>"; $fp = @fsockopen($host, $port, $errno, $errstr); if ($fp) { echo "Socket connection established"; fclose($fp); } else { echo "Could not connect to $host at port $port (\$errno=$errno; \$errstr=$errstr)"; } ?> </h2> </html> When I run it through a Web browser $fp is null, $errno is 0 and $errstr is empty. When I run it from a command line, using the IIS Internet user's credentials, the connection succeeds and $fp is non-null. I would appreciate any suggestions.