Implementing and Operating Cisco Enterprise Network Core Technologies (ENCOR) v1.2InfrastructureEasy
A network engineer is configuring a new Cisco router to support a remote branch office. The branch office uses private IPv4 addresses and needs to access external public resources. The engineer wants to conserve public IP addresses by allowing multiple internal hosts to share a single public IP address. Which NAT type should be configured?
- ANAT Overload (PAT)
- BStatic NAT
- CDynamic NAT
- DNAT64
Show answer & explanationAnswer & explanation
Correct answer: A. NAT Overload (PAT)
NAT Overload, also known as Port Address Translation (PAT), allows multiple internal private IP addresses to be translated to a single public IP address by using different port numbers. This is the most common form of NAT for conserving public IP addresses.
Why the other options are wrong
- B. Static NAT maps a single private IP to a single public IP, not conserving addresses.
- C. Dynamic NAT maps multiple private IPs to a pool of public IPs, also not conserving to a single public IP.
- D. NAT64 is used for IPv6 to IPv4 translation, not relevant for IPv4 address conservation in this scenario.
NAT Overload (PAT)
A form of Network Address Translation (NAT) that maps multiple internal private IP addresses to a single public IP address by using unique source port numbers.
- Also known as Port Address Translation (PAT).
- Most common type of NAT for Internet access.
- Significantly conserves public IP addresses.
Memory trick: NAT's Many Faces: One-to-One, Pool, or Many-to-One.