PHP Function Reference

PHP getservbyname() Function

The PHP getservbyname() function returns the Internet port number associated with an specified service for the specified protocol. The function returns false if the service or protocol is not found.


getservbyname(service, protocol)


service Required. Specify the Internet service name, as a string.
protocol Required. Specify protocol which is either "tcp" or "udp" (in lowercase).

Return Value

Returns the port number, or false if service or protocol is not found.


The example below shows the usage of getservbyname() function.

//array containing services as string elements
$services = array('http', 'ftp', 'ssh', 'telnet', 'imap',
'smtp', 'nicname', 'gopher', 'finger', 'pop3', 'www');

//finding the port number associated with 
//above services for "tcp" protocol
foreach ($services as $service) {
  $port = getservbyname($service, 'tcp');
  echo $service .": " . $port . "\n";

The output of the above code will be:

http: 80
ftp: 21
ssh: 22
telnet: 23
imap: 143
smtp: 25
nicname: 43
gopher: 70
finger: 79
pop3: 110
www: 80

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