Cisco CCNA (200-301)IP ServicesEasy
A network administrator is configuring a Cisco router to translate internal private IPv4 addresses to a single public IPv4 address for external internet access. Which type of NAT is being configured?
- APAT
- BNAT64
- CDynamic NAT
- DStatic NAT
Show answer & explanationAnswer & explanation
Correct answer: A. PAT
Port Address Translation (PAT) is a form of NAT that maps multiple private IP addresses to a single public IP address by using different port numbers. This allows many internal devices to share one public IP.
Why the other options are wrong
- B. NAT64 is used for translating IPv6 packets to IPv4 packets and vice versa, which is not the scenario described.
- C. Dynamic NAT maps multiple private IPs to a pool of public IPs, but typically still uses a 1:1 mapping for each active session, not sharing a single public IP for all.
- D. Static NAT maps one private IP to one public IP and does not allow multiple devices to share a single public IP.
Port Address Translation (PAT)
A type of Network Address Translation (NAT) that maps multiple private IP addresses to a single public IP address by using unique source port numbers.
- Also known as NAT Overload.
- Efficiently conserves public IPv4 addresses.
- Uses distinct port numbers to differentiate internal hosts.
Memory trick: Private homes share ONE public gate with many keys.