Implementing and Operating Cisco Enterprise Network Core Technologies (ENCOR) v1.2InfrastructureEasy
A network technician is configuring a Cisco router to provide Internet access for a small office. The office has a single public IP address (203.0.113.10) and an internal private network (192.168.1.0/24). All internal devices need to share the single public IP address for outbound Internet access. Which NAT configuration type should the technician implement?
- ADynamic NAT
- BPort Address Translation (PAT)
- CStatic NAT
- DNAT64
Show answer & explanationAnswer & explanation
Correct answer: B. Port Address Translation (PAT)
Port Address Translation (PAT), also known as NAT Overload, allows multiple private IP addresses to share a single public IP address by using different source port numbers. This is the most common form of NAT for small offices sharing one public IP.
Why the other options are wrong
- A. Dynamic NAT maps a pool of private IP addresses to a pool of public IP addresses, requiring multiple public IPs.
- C. Static NAT maps a single private IP address to a single public IP address, which doesn't allow multiple devices to share one public IP.
- D. NAT64 is used for translating between IPv6 and IPv4 networks, which is not applicable here.
Port Address Translation (PAT)
A form of NAT that allows multiple private IP addresses to share a single public IP address by mapping different source port numbers.
- Also known as NAT Overload.
- Conserves public IP addresses.
- Most commonly used for home and small office Internet access.
Memory trick: PAT is the party where everyone shares one door.