How can PHP developers ensure the security and accuracy of user data when handling IP addresses and hostnames in their code?

To ensure the security and accuracy of user data when handling IP addresses and hostnames in PHP code, developers should validate and sanitize input data to prevent injection attacks and ensure that only valid IP addresses and hostnames are accepted. This can be achieved by using PHP filter functions like filter_var() with the FILTER_VALIDATE_IP and FILTER_VALIDATE_DOMAIN filters.

// Validate and sanitize user input for IP address
$user_ip = filter_input(INPUT_POST, 'ip_address', FILTER_VALIDATE_IP);

if($user_ip){
    // Valid IP address, proceed with processing
} else {
    // Invalid IP address, handle error
}

// Validate and sanitize user input for hostname
$user_hostname = filter_input(INPUT_POST, 'hostname', FILTER_VALIDATE_DOMAIN);

if($user_hostname){
    // Valid hostname, proceed with processing
} else {
    // Invalid hostname, handle error
}