Implementing and Operating Cisco Enterprise Network Core Technologies (ENCOR) v1.2InfrastructureMedium
A network engineer needs to configure a Cisco router to translate internal private IP addresses to a single public IP address when accessing the internet. This setup should allow multiple internal hosts to share the same public IP. Which NAT type should be configured?
- APAT (Port Address Translation)
- BDynamic NAT
- CNAT64
- DStatic NAT
Show answer & explanationAnswer & explanation
Correct answer: A. PAT (Port Address Translation)
PAT (Port Address Translation), also known as NAT Overload, allows multiple internal private IP addresses to share a single public IP address by using different source port numbers. This is the most common form of NAT used for internet access in small to medium-sized networks.
Why the other options are wrong
- B. Dynamic NAT maps internal private IP addresses to a pool of public IP addresses on a one-to-one basis, but doesn't allow multiple private IPs to share a single public IP simultaneously.
- C. NAT64 is used for translating between IPv6 and IPv4 networks, which is not the scenario described.
- D. Static NAT provides a one-to-one mapping between a private and a public IP address, not sharing a single public IP.
Port Address Translation (PAT)
A form of Network Address Translation (NAT) that allows multiple devices on a private network to share a single public IP address by using unique source port numbers.
- Also known as NAT Overload.
- Most common NAT type for internet access in homes and small businesses.
- Conserves public IP addresses.
Memory trick: NAT: Many to One? PAT's the Fun!