(PHP 4, PHP 5)
getservbyname — Get port number associated with an Internet service and protocol
$service
   , string $protocol
   )
   getservbyname() returns the Internet port
   which corresponds to service for the
   specified protocol as per
   /etc/services.
  
serviceThe Internet service name, as a string.
protocol
       protocol is either "tcp"
       or "udp" (in lowercase).
      
   Returns the port number, or FALSE if service or
   protocol is not found.
  
Example #1 getservbyname() example
<?php
$services = array('http', 'ftp', 'ssh', 'telnet', 'imap',
'smtp', 'nicname', 'gopher', 'finger', 'pop3', 'www');
foreach ($services as $service) {
    $port = getservbyname($service, 'tcp');
    echo $service . ": " . $port . "<br />\n";
}
?>