1.3.8 Do not disclose private IP addresses and routing information to unauthorized parties.
Note: Methods to obscure IP addressing may include, but are not limited to:
* Network Address Translation (NAT)
* Placing servers containing cardholder data behind proxy servers/firewalls or content caches,
* Removal or filtering of route advertisements for private networks that employ registered addressing,
* Internal use of RFC1918 address space instead of registered addresses.