A network administrator is configuring an enterprise edge firewall to allow 150 internal hosts on a private subnet () to simultaneously access external resources on the Internet. The Internet Service Provider (ISP) has allocated only one public IPv4 address to the company. Which translation method should the administrator implement to meet this requirement?
- Port Address Translation (PAT), because it maps internal IP addresses and unique Layer 4 source ports to a single public IP address.Answer
- BStatic NAT, because it creates a permanent one-to-one mapping between each internal private IP address and the single public IP address.
- CDynamic NAT, because it translates Layer 3 IP headers from an internal address pool without examining or modifying Layer 4 port information.
- DDestination NAT, because it rewrites the destination service port on incoming packets to route traffic back to the originating internal host.
Answer
Port Address Translation (PAT) should be implemented because it multiplexes multiple private IP addresses onto a single public IP address by tracking unique Layer 4 transport ports.
Port Address Translation (PAT), also known as NAT Overload, assigns a unique source port number to each internal host's outbound session. This allows up to thousands of concurrent outbound connections from multiple private hosts to share one single public IPv4 address.
Step-by-Step Solution
Key Concept
Port Address Translation (PAT / NAT Overload)