Which device is typically placed at the network edge to route traffic between internal networks and the Internet, including handling translations?

Which device is typically placed at the network edge to route traffic between internal networks and the Internet, including handling translations?

• A. Internet Gateway
• B. NAT Gateway
• C. Proxy Server
• D. XML Gateway

Answer: (B)

At the edge of a network you want a device that can both route traffic between internal hosts and the Internet and rewrite IP addresses so multiple internal devices can share a public address. This is what NAT—the Network Address Translation mechanism—does. A NAT gateway sits at the network border and translates private IP addresses of internal devices to a public IP (or a pool of public IPs) as traffic leaves the network. It may also handle port translation so many internal sessions are distinguished on the outside, enabling proper return traffic. This makes NAT gateway the best fit for handling both routing and address translation at the edge.

An Internet gateway is a broad term for a device that connects to the Internet but doesn’t by itself imply address translation. A proxy server operates at the application layer, acting on behalf of clients to fetch resources rather than routing all traffic at the network layer. An XML gateway specializes in processing XML messages, not general IP routing or translation.