Question

Difficulty: HardNAT and PAT Implementation

Match each enterprise address translation requirement or descriptor on the left with the corresponding Network Address Translation (NAT) implementation type or address classification on the right.

  • Providing permanent, bi-directional inbound accessibility to an internal server residing on a private subnet using a fixed one-to-one IP mapping.Static NAT
  • Allowing hundreds of internal workstations to establish outbound internet connections simultaneously over a single public IP by tracking unique ephemeral Layer 4 source ports.Port Address Translation (PAT / NAT Overload)
  • Assigning an internal host a temporary public IP address from a pre-configured, bounded address pool on a first-come, first-served basis for the duration of its session.Dynamic NAT
  • The public IPv4 address assigned to represent an internal private host to external entities on the public internet.Inside Global Address

Answer

The correct matches are: 1. Permanent bi-directional inbound accessibility matches Static NAT; 2. Multiple workstations sharing a single public IP via Layer 4 source ports matches Port Address Translation (PAT / NAT Overload); 3. Assigning a temporary public IP from a pre-configured pool matches Dynamic NAT; 4. The public IPv4 address assigned to represent an internal host externally matches Inside Global Address.
Each NAT mechanism serves specific architectural requirements: Static NAT maintains a 1-to-1 static mapping for inbound services; PAT (Overload) multiplexes multiple private IPs across one public IP by translating Layer 4 source ports; Dynamic NAT allocates public IPs dynamically from a pool on a 1-to-1 basis; and Inside Global refers specifically to the translated public address representing an inside device to the outside world.

Step-by-Step Solution

1
Analyze requirement 1 (permanent bi-directional inbound access).
Identified as requiring a static, invariant 1-to-1 mapping.
Static NAT ensures outside clients can consistently initiate connections to an internal server.
2
Analyze requirement 2 (hundreds of workstations sharing one public IP via source ports).
Identified as Port Address Translation (PAT).
PAT uses Layer 4 TCP/UDP port mapping (Overload) to multiplex many internal private addresses over a single public address.
3
Analyze requirement 3 (temporary IP assignment from a bounded pool).
Identified as Dynamic NAT.
Dynamic NAT creates temporary 1-to-1 translations on demand from an available address pool.
4
Analyze requirement 4 (naming convention for the public representation of an internal host).
Identified as Inside Global Address.
CompTIA/Cisco terminology defines Inside Global as the translated address of an inside device as viewed by external networks.

Key Concept

NAT/PAT Implementation Types and CompTIA Network Address Classifications
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