Show part of a IP address

Question

85.124.99.2

How can I hide the last two numbers from the IP?

and make it like:

86.124.xxx.xxx

Answer 1

Wrote this quickly

$ip = "85.124.99.2";
$parts = explode('.',$ip);

$new_ip = $parts[0].'.'.$parts[1].'.xxx.xxx';

Warning: You should test the length of parts before accessing $parts[n]

Answer 2

$ip = preg_replace('/\.\d+\.\d+$/', '.xxx.xxx', $ip);