CCNA Network Infrastructure and Connectivity Practice Question
A junior administrator is asked to configure a Cisco router interface with the IPv4 address 10.1.1.1 and a subnet mask of 255.255.255.0 so it can route traffic for the 10.1.1.0/24 network. Which command correctly assigns this address to the interface?
⚠ Common exam trap
The trap here is mixing CIDR slash notation or non-IOS keywords into a command that requires a dotted-decimal mask.
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 address 10.1.1.1 255.255.255.0
Cisco IOS interface configuration uses the ip address command with the address and a dotted-decimal subnet mask, so ip address 10.1.1.1 255.255.255.0 is correct. Slash notation, the ipv4 keyword, and an extra mask keyword are all invalid in this context. Getting the exact syntax right is essential because a rejected command leaves the interface unaddressed and unable to route for the 10.1.1.0/24 network.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
ipv4 address 10.1.1.1 255.255.255.0
Why it's wrong here
The keyword ipv4 is not used in this form on Cisco IOS router interfaces for IPv4 addressing. The correct command keyword is simply ip address. Using ipv4 address would produce an unrecognized command error and leave the interface without an address, so it fails to meet the requirement.
- ✗
ip address 10.1.1.1 mask 255.255.255.0
Why it's wrong here
Cisco IOS does not use the keyword mask between the address and the subnet mask in the ip address command. The syntax is ip address followed directly by the address and mask. Including the extra keyword causes the command to be rejected, so the interface would not receive the intended IPv4 configuration.
- ✓
ip address 10.1.1.1 255.255.255.0
Why this is correct
The ip address command on a Cisco router interface accepts the address followed by a dotted-decimal subnet mask, so ip address 10.1.1.1 255.255.255.0 correctly assigns the address and mask. This is the standard syntax used in interface configuration mode and produces the intended 10.1.1.0/24 network on that interface.
- ✗
ip address 10.1.1.1/24
Why it's wrong here
Cisco IOS does not accept CIDR slash notation directly in the ip address command; the mask must be entered in dotted-decimal form or the command is rejected with an error. While slash notation is common in documentation and on other platforms, it is not valid syntax here. The correct approach is to supply 255.255.255.0 as the mask argument.
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Key term
IP address
An IP address is a unique numerical label assigned to each device connected to a computer network that uses the Internet Protocol for communication.
Key term
IPv4
IPv4 is the fourth version of the Internet Protocol, a set of rules that assigns unique numerical addresses to devices so they can communicate over networks like the internet.
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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 200-301 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 200-301 exam.