300-410 Infrastructure Services Practice Question
A network engineer is configuring a Cisco router to support Network Address Translation (NAT) for a small office. The engineer wants to translate internal private addresses to a single public address using Port Address Translation (PAT). Which command enables PAT by allowing the router to use the interface's IP address for translation?
⚠ Common exam trap
The trap here is forgetting the overload keyword, which is required for PAT, and confusing interface-based PAT with pool-based PAT.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
ip nat inside source list 1 interface GigabitEthernet0/0 overload
PAT is enabled by using the overload keyword with the ip nat inside source command. When translating to an interface address, the syntax includes the interface keyword and overload. The correct command references the access list defining inside traffic, specifies the outside interface, and includes overload. Other options either use a pool, perform static translation, or omit overload, so they do not achieve PAT using the interface address.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
ip nat inside source list 1 interface GigabitEthernet0/0
Why it's wrong here
This command is missing the overload keyword. Without overload, the router would attempt to perform dynamic NAT without PAT, which requires a one-to-one mapping of inside addresses to outside addresses. Since only one interface address is used, it would only support a single translation. The overload keyword is necessary to enable PAT. Thus, this option is incorrect.
- ✗
ip nat inside source static 10.1.1.1 203.0.113.1
Why it's wrong here
This command creates a static NAT translation for a single inside host to a specific outside address. It does not enable PAT or allow multiple hosts to share a single public address. Static NAT is used for one-to-one mapping, not for overload. Therefore, it is incorrect for this scenario.
- ✓
ip nat inside source list 1 interface GigabitEthernet0/0 overload
Why this is correct
This command configures PAT by referencing an access list (list 1) that defines the internal traffic to be translated and using the interface GigabitEthernet0/0's IP address as the public address. The overload keyword enables PAT, allowing multiple internal hosts to share the single public IP address by using different source ports. This is the correct command for the scenario.
- ✗
ip nat inside source list 1 pool PUBLIC_POOL overload
Why it's wrong here
This command uses a pool of public addresses for translation with overload, which enables PAT but uses a pool instead of the interface's IP address. The scenario specifies using the interface's IP address, so this command does not meet the requirement. It is a valid configuration for PAT with a pool, but not for using the interface address.
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JA
Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official Cisco exam blueprint
This 300-410 practice question is part of Courseiva's free Cisco certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the 300-410 exam.