Cisco Certified Support Technician (CCST) NetworkingIP ConnectivityMedium
A network technician is troubleshooting an issue where internal users can access external websites, but external users cannot initiate connections to an internal web server. The internal web server has a private IP address. Which NAT type is most likely missing or misconfigured?
- AStatic NAT
- BPort Address Translation (PAT)
- CNAT Overload
- DDynamic NAT
Show answer & explanationAnswer & explanation
Correct answer: A. Static NAT
Static NAT is used to map a private IP address to a specific public IP address, allowing external devices to initiate connections to internal servers. Without it, the internal web server is unreachable from the outside.
Why the other options are wrong
- B. PAT (often called NAT Overload) allows multiple internal hosts to share a single public IP address using different port numbers, primarily for outbound connections.
- C. NAT Overload is another term for PAT, which is used for outbound connections and doesn't solve the inbound access issue for a server.
- D. Dynamic NAT allows internal hosts to share a pool of public IP addresses for outbound connections, but doesn't allow unsolicited inbound connections.
Static NAT
Static NAT provides a one-to-one, permanent mapping between a private IP address and a public IP address, allowing external access to internal resources.
- Used for servers accessible from the internet.
- Requires a dedicated public IP for each internal host.
- Mapping is always active and doesn't expire.
Memory trick: Servers Need A Transparent Inbound Connection: Static NAT.