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Difficulty: MediumNAT and PAT Implementation

Match each enterprise address translation requirement or scenario on the left with the correct NAT/PAT implementation method or routing behavior on the right.

  • Providing an inbound persistent public IP mapping for an internal DMZ web server requiring fixed external accessStatic NAT (1:1 Translation)
  • Multiplexing thousands of internal client outbound sessions onto a single public IP address using unique transport layer portsPort Address Translation (PAT / NAT Overload)
  • Assigning temporary, dynamic public IP addresses from a limited public subnet pool to active internal outbound hostsDynamic NAT (Pool Translation)
  • Forwarding packets across internal subnets where host IP header addresses remain unchanged through transitNative IP Routing (No NAT)

Answer

Inbound persistent web server hosting corresponds to Static NAT (1:1 Translation). Outbound session multiplexing using unique transport ports corresponds to Port Address Translation (PAT / NAT Overload). Assigning temporary public IPs from a defined subnet pool corresponds to Dynamic NAT (Pool Translation). Packet forwarding without address alteration corresponds to Native IP Routing (No NAT).
Each requirement directly aligns with standard network implementation terminology: Static NAT provides a fixed 1:1 public-to-private IP mapping ideal for inbound public services; PAT (NAT Overload) allows many hosts to share a single public IP via port multiplexing; Dynamic NAT draws temporary 1:1 public addresses from a pool; and Native IP Routing forwards packets without translating IP header address fields.

Step-by-Step Solution

1
Analyze the requirement for hosting inbound services that require a consistent external identity.
Identify that persistent one-to-one mapping between inside local and inside global addresses is provided by Static NAT.
Static NAT provides a dedicated permanent public IP address so external clients can reach internal servers.
2
Analyze the requirement for sharing a single public IP address across multiple outbound client sessions.
Identify that mapping multiple internal IP addresses to one public IP via unique Layer 4 port tracking is performed by PAT (NAT Overload).
PAT tracks source ports at the transport layer to differentiate session traffic from distinct internal hosts sharing a common public IP.
3
Analyze the requirement for dynamic one-to-one temporary mapping from a public IP pool.
Identify that assigning available public addresses on demand from a configured range is performed by Dynamic NAT.
Dynamic NAT dynamically maps inside local addresses to available inside global addresses from a public address pool.
4
Analyze packet forwarding without modifying IP header addresses.
Identify that routing without address translation represents Native IP Routing.
Standard IP routing forwards packets based on routing table lookups without performing Network Address Translation.

Key Concept

NAT and PAT address mapping types and operational requirements
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Topics

NAT and PAT Implementation

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