(PHP 4, PHP 5, PHP 7, PHP 8)
getservbyport — Get Internet service which corresponds to port and protocol
$port, string $protocol): string|false
getservbyport() returns the Internet service
associated with port for the specified
protocol as per /etc/services.
portThe port number.
protocol
protocol is either "tcp"
or "udp" (in lowercase).
Returns the Internet service name as a string, 或者在失败时返回 false.