CCNP Security Practice Question
An engineer must secure the management plane of a Cisco IOS XE router so that only SSH version 2 is accepted for remote administration, while Telnet and SSHv1 are rejected. Which set of commands accomplishes this?
⚠ Common exam trap
The trap here is believing that disabling SSHv1 requires a 'no' form command, when the correct approach is to explicitly set 'ip ssh version 2'.
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
✓
line vty 0 4 transport input ssh ip ssh version 2
Restricting VTY lines with 'transport input ssh' eliminates Telnet access, and 'ip ssh version 2' forces the SSH server to negotiate only version 2. Used together under the correct configuration modes, they enforce SSHv2-only remote management. Other combinations either leave Telnet enabled, use invalid syntax, or fail to restrict the transport protocol.
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 ssh server algorithm encryption aes128-ctr aes256-ctr line vty 0 4 transport input all
Why it's wrong here
Restricting encryption algorithms does not prevent SSHv1 or Telnet from being used. The 'transport input all' command explicitly permits Telnet and SSH on the VTY lines, which contradicts the requirement. This configuration weakens rather than strengthens management-plane security.
- ✗
line vty 0 4 transport input telnet ssh ip ssh version 2
Why it's wrong here
Allowing both telnet and ssh on the VTY lines leaves Telnet enabled, which transmits credentials in cleartext and violates the requirement to reject Telnet. Although SSHv2 is enforced for SSH sessions, the Telnet exposure means the management plane remains insecure and the scenario's goal is not met.
- ✓
line vty 0 4 transport input ssh ip ssh version 2
Why this is correct
The transport input ssh command restricts VTY lines to SSH only, blocking Telnet, while ip ssh version 2 forces the router to negotiate only SSHv2 sessions. Together they satisfy both requirements. This is the canonical method on Cisco IOS XE for enforcing SSHv2-only management access.
- ✗
line vty 0 4 transport input ssh no ip ssh version 1
Why it's wrong here
The 'no ip ssh version 1' command is not valid syntax on Cisco IOS XE. The correct way to force SSHv2 is 'ip ssh version 2'. Because the second command is invalid, the router would reject it, and SSHv1 could still be negotiated, failing the requirement.
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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.