Cisco Certified Support Technician (CCST) NetworkingIP ConnectivityEasy
A network technician is configuring a router for a small office network. The office uses private IP addresses (192.168.1.0/24) internally and needs to access the internet. Which type of Network Address Translation (NAT) is most suitable if multiple internal hosts need to share a single public IP address for outbound connections?
- ADynamic NAT without overload
- BPort Address Translation (PAT)
- CNAT64
- DStatic NAT
Show answer & explanationAnswer & explanation
Correct answer: B. Port Address Translation (PAT)
Port Address Translation (PAT), also known as NAT overload, allows multiple internal private IP addresses to share a single public IP address by using different port numbers. This is the most common form of NAT for home and small office networks.
Why the other options are wrong
- A. Dynamic NAT without overload maps a pool of private IPs to a pool of public IPs, requiring as many public IPs as concurrent internal users.
- C. NAT64 is specifically for translating between IPv6 and IPv4 networks, not for sharing a single public IPv4 address.
- D. Static NAT maps one private IP to one public IP, which is not suitable for sharing a single public IP among many hosts.
Port Address Translation (PAT)
A form of Network Address Translation (NAT) that allows multiple private IP addresses to share a single public IP address by using unique port numbers for each translation.
- Also known as NAT overload.
- Uses port numbers to distinguish between internal hosts.
- Most common type of NAT for internet access in small networks.
Memory trick: Many homes, one street address, different doors.