Cisco Certified Support Technician (CCST) NetworkingIP ConnectivityMedium
A network technician is configuring Static Network Address Translation (NAT) on a Cisco router. The internal server has an IP address of 192.168.1.10, and it needs to be accessible from the internet using the public IP address 203.0.113.5. Which command correctly configures this Static NAT mapping?
- Aip nat outside source static 203.0.113.5 192.168.1.10
- Bip nat inside source list NAT_POOL interface GigabitEthernet0/1 overload
- Cip nat inside source dynamic 192.168.1.10 203.0.113.5
- Dip nat inside source static 192.168.1.10 203.0.113.5
Show answer & explanationAnswer & explanation
Correct answer: D. ip nat inside source static 192.168.1.10 203.0.113.5
The 'ip nat inside source static' command is used to create a one-to-one mapping between an internal local IP address and an internal global IP address for static NAT. The internal local IP is the private address, and the internal global IP is the public address.
Why the other options are wrong
- A. The 'outside source static' command is used for mapping outside addresses to different outside addresses, not internal servers.
- B. This command configures dynamic NAT with PAT (overload) using an access list and an interface, which is not static NAT.
- C. The 'dynamic' keyword is used for dynamic NAT, not static NAT, and the syntax is incorrect for dynamic NAT.
Static NAT Configuration
Static NAT creates a permanent one-to-one mapping between a private IP address and a public IP address, allowing external devices to initiate connections to an internal host.
- Uses 'ip nat inside source static <local-ip> <global-ip>'.
- Requires one public IP address per internal host.
- Commonly used for servers accessible from the internet.
Memory trick: NAT is like a translator, static is a fixed dictionary entry.