A network administrator needs to configure address translation on an enterprise perimeter router. The network environment requires external users on the internet to reach an internal email server () and an internal web server () using distinct, permanent public IPv4 addresses. Simultaneously, internal corporate workstations residing on private subnets must be able to access internet resources using a single remaining public IPv4 address. Which combination of translation methods best fulfills these requirements?
- Configure Static NAT for both the email and web servers, and Port Address Translation (PAT) for the internal workstations.Answer
- BConfigure Static NAT for all internal workstations as well as the email and web servers.
- CConfigure Layer 2 MAC Address Translation for the servers and Dynamic NAT without overload for the workstations.
- DConfigure Port Address Translation (PAT) locked to TCP port 25 for all workstations and Static NAT for the web server.
Answer
Configure Static NAT for both the email and web servers, and Port Address Translation (PAT) for the internal workstations.
Static NAT maps a single internal private IP address to a single external public IP address consistently, which is necessary for external hosts to locate and initiate connections to inbound services like web and email servers. Port Address Translation (PAT), also known as NAT Overload, modifies both the source IP address and source port number of outbound traffic, permitting multiple private host IP addresses to share a single public IPv4 address efficiently.
Step-by-Step Solution
Key Concept
Static NAT vs. Port Address Translation (PAT/Overload) implementation criteria