hardMultiple Choice
300-410 Management traffic is being dropped Practice Question
Management traffic is being dropped. Router R1 has: access-list 100 deny ip any any log, applied to VTY lines. Remote access via SSH fails, but console works. What is the root cause?
⚠ Common exam trap
Many exam-takers think the ACL is applied to an interface (Option C) or that the `log` keyword causes the problem, when in fact the issue is the order of ACL entries—specifically, the missing permit for SSH before the global deny.
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
✓
The ACL should permit SSH before the deny statement.
The ACL `access-list 100 deny ip any any log` applied to VTY lines denies all IP traffic, including SSH, before any permit statement can match. Since SSH traffic is denied, remote access fails. The correct fix is to add a `permit tcp any any eq 22` statement before the deny to allow SSH management 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.
- ✓
The ACL should permit SSH before the deny statement.
Why this is correct
The ACL ends with an implicit or explicit deny, and no permit for TCP port 22 precedes it, so SSH traffic to the VTY lines is dropped. Console access bypasses VTY line ACLs, which is why it still works. Adding a permit for SSH before the deny resolves the failure.
- ✗
The VTY lines require transport input ssh, but the ACL is irrelevant.
Why it's wrong here
SSH is already failing because the ACL's deny ip any any entry drops inbound management sessions on the VTY lines, not because transport input is misconfigured. Restricting transport input to ssh is correct when a device must accept only encrypted management protocols.
- ✗
The ACL is applied to the wrong interface.
Why it's wrong here
Applying the ACL to an interface would filter transit traffic, not VTY access; here it is already bound to the VTY lines, where the deny any any entry blocks SSH. Interface ACLs are the right tool for filtering data-plane traffic entering or leaving a router port.
- ✗
The log keyword causes performance issues, not drops.
Why it's wrong here
The log keyword only records matching packets to syslog; it does not itself drop traffic. The deny statement drops all IP traffic, including SSH, before any permit line, so VTY access fails. Logging would be relevant when auditing which packets an ACL matches, not as the cause of the drop.
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
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.