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Zorluk: OrtaNAT and PAT Implementation

A network engineer is setting up an edge router for a small office with only a single public IPv4 address assigned to its WAN interface. The office contains 40 internal hosts on the 192.168.1.0/24192.168.1.0/24 subnet that require outbound internet connectivity. Simultaneously, an internal web server at 192.168.1.50192.168.1.50 must be reachable from external clients on HTTPS port 443443. Which of the following address translation strategies correctly satisfies both requirements using the single WAN IPv4 address?

  1. Implement Port Address Translation (PAT) for the internal host subnet while configuring a static port redirection (Port Forwarding) entry for port 443443 to target internal address 192.168.1.50192.168.1.50.Cevap
  2. B
    Assign a 1:1 Static NAT mapping to the internal web server and configure Dynamic NAT without overload for the remaining 40 internal workstations.
  3. C
    Configure Layer 2 MAC Address Translation to bridge the internal web server to the WAN interface while running Static NAT on destination port 8080 for workstation internet access.
  4. D
    Deploy Port Address Translation (PAT) restricted strictly to Layer 3 IP headers, translating destination port 2222 to direct external HTTPS connections to the internal server.

Cevap

Implement Port Address Translation (PAT) for the internal subnet alongside static port forwarding for port 443 to host 192.168.1.50.
Port Address Translation (PAT), also known as NAT Overload, enables multiple private IP hosts to share a single public IPv4 address by mapping outbound connections to distinct Layer 4 source ports. To allow external traffic to initiate a connection inward to a specific internal server using that same shared public IP, static port forwarding must be configured for the specific service port (HTTPS port 443).

Adım Adım Çözüm

1
Analyze public IP address constraints
Only one public IPv4 address is available on the WAN interface.
Because multiple internal hosts need internet access using a single public IP address, Port Address Translation (PAT / NAT Overload) must be used to multiplex outbound sessions using unique source port numbers.
2
Determine inbound access requirements for the web server
Inbound HTTPS traffic target port is 443 assigned to internal IP 192.168.1.50.
To allow external clients to initiate connections to an internal server sharing a single public IP, a static PAT entry (port forwarding) must be configured to direct incoming traffic arriving on destination port 443 to the internal IP.
3
Combine translation rules into a unified implementation
Dynamic PAT handles outbound host traffic while Static PAT handles inbound HTTPS traffic.
This combination successfully meets both requirements without requiring additional public IPv4 addresses.

Anahtar Kavram

Port Address Translation (PAT) and Static Port Forwarding
Tahmini Süre:1m 15s
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Konular

NAT and PAT Implementation

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