Why deploy IPv4 private addressing?

IPv4 private addressing (RFC 1918) enhances security by preventing direct access to internal network devices from the internet. Devices with private IP addresses cannot be reached directly from public networks, creating a barrier that reduces the attack surface and the risk of external breaches. Network Address Translation (NAT) is used to allow private IP devices to access the internet, but it doesn't expose them directly. PCI regulations focus on securing cardholder data, not specifically on private IP addressing. While private addressing is part of a secure network design, it's not the sole reason for PCI compliance. Reducing forwarding table size is primarily achieved through route summarization and hierarchical addressing, not private addressing. Local laws typically don't mandate private IP address usage.