Cisco CCNA (200-301)IP ServicesEasy
A network administrator is configuring a Cisco router to perform Network Address Translation (NAT). They need to ensure that internal hosts can access external resources and that all internal private IP addresses are translated to a single public IP address. Which type of NAT should be configured?
- ADynamic NAT
- BStatic NAT
- CNAT64
- DPort Address Translation (PAT)
Show answer & explanationAnswer & explanation
Correct answer: D. Port Address Translation (PAT)
Port Address Translation (PAT) allows multiple private IP addresses to be translated to a single public IP address by using different port numbers, enabling many internal hosts to share one public IP for internet access.
Why the other options are wrong
- A. Dynamic NAT maps a pool of private IP addresses to a pool of public IP addresses, requiring a 1:1 mapping at any given time.
- B. Static NAT maps a single private IP address to a single public IP address.
- C. NAT64 is used for translating between IPv6 and IPv4 networks, which is not the scenario described.
Port Address Translation (PAT)
A form of NAT that allows multiple devices on a private network to share a single public IP address by mapping different private IP addresses and port numbers to the same public IP address and unique port numbers.
- Many-to-one translation
- Uses port numbers to differentiate connections
- Conserves public IPv4 addresses
Memory trick: Many homes share one door to the world, each with a unique key.