CCNP Infrastructure Practice Question
A network administrator is deploying a new Cisco Catalyst switch and wants to restrict management access to the switch. The requirement is that only hosts on the 10.10.10.0/24 subnet can access the switch via SSH, and all other SSH attempts must be denied. Which configuration achieves this?
⚠ Common exam trap
The trap here is applying an ACL to an interface instead of the VTY lines, or using an extended ACL when a standard ACL is sufficient, which can lead to unintended filtering or lack of restriction.
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
✓
access-list 10 permit 10.10.10.0 0.0.0.255; line vty 0 4; access-class 10 in
Using a standard ACL that permits the 10.10.10.0/24 subnet and applying it inbound on the VTY lines with access-class restricts SSH and Telnet access to only that subnet. The implicit deny at the end blocks all other sources, satisfying the requirement without affecting other traffic.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
access-list 10 permit 10.10.10.0 0.0.0.255; interface vlan 1; ip access-group 10 in
Why it's wrong here
Applying an ACL to the management VLAN interface filters traffic entering the switch's management interface, but it does not specifically restrict VTY access. It could block other traffic and does not directly control SSH sessions. The requirement is to restrict SSH access, so this is not the correct approach.
- ✓
access-list 10 permit 10.10.10.0 0.0.0.255; line vty 0 4; access-class 10 in
Why this is correct
This configuration creates a standard ACL that permits the 10.10.10.0/24 subnet and applies it inbound to the VTY lines with access-class. This restricts SSH and Telnet access to only that subnet, meeting the requirement. The implicit deny at the end of the ACL blocks all other sources.
- ✗
access-list 10 deny 10.10.10.0 0.0.0.255; line vty 0 4; access-class 10 in
Why it's wrong here
This ACL denies the permitted subnet and, due to the implicit deny, would deny all traffic, including the allowed subnet. This is the opposite of the requirement. The correct approach is to permit the subnet and rely on the implicit deny for others.
- ✗
access-list 110 permit tcp 10.10.10.0 0.0.0.255 any eq 22; line vty 0 4; access-class 110 in
Why it's wrong here
This extended ACL permits TCP port 22 from the subnet, but applying an extended ACL with access-class on VTY lines is not supported in all IOS versions and may not work as intended. The scenario requires restricting all management access, not just SSH, and a standard ACL is simpler and more appropriate.
Visual reference
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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 350-401 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 350-401 exam.