The correct answer is that authentication will fall back to the local user database when the TACACS+ server is unreachable. This happens because Cisco IOS and IOS-XE switches enable the fallback-to-local feature by default for TACACS+ configurations, meaning that if the AAA server at 10.1.1.1 does not respond, the device automatically uses locally configured usernames and passwords to authenticate SSH access. On the Cisco DCCOR 350-601 exam, this concept tests your understanding of AAA redundancy and the default behavior of TACACS+ fallback to local authentication—a common trap is assuming that authentication simply fails or that the switch uses the enable password instead. Remember that fallback-to-local is enabled by default, so administrative access is preserved even when the remote server is down. A helpful memory tip: think of it as “TACACS+ first, local last—by default, you’re never locked out.”
350-601 Security Practice Question
This 350-601 practice question tests your understanding of security. This is a configuration task: choose the command set that satisfies every stated requirement. Small differences — like 'secret' vs 'password' or 'transport input ssh' vs 'all' — change whether the answer is correct. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
Exhibit
Refer to the exhibit.
! Output from show running-config | section security
!
feature tacacs+
tacacs-server host 10.1.1.1 key ciscosecret
tacacs-server directed-request
aaa authentication login default group tacacs+ local
aaa authentication enable default group tacacs+ local
aaa authorization commands default group tacacs+ local
aaa accounting commands default group tacacs+
Refer to the exhibit. The TACACS+ server at 10.1.1.1 is unreachable. What will happen when a user tries to authenticate to the switch using SSH?
Refer to the exhibit.
! Output from show running-config | section security
!
feature tacacs+
tacacs-server host 10.1.1.1 key ciscosecret
tacacs-server directed-request
aaa authentication login default group tacacs+ local
aaa authentication enable default group tacacs+ local
aaa authorization commands default group tacacs+ local
aaa accounting commands default group tacacs+
A
Authentication will use the local user database as a fallback.
The 'local' keyword provides fallback.
B
Authentication will be denied immediately.
Why wrong: There is a fallback to local authentication.
C
Authentication will be attempted against the TACACS+ server repeatedly until timeout.
Why wrong: It will fallback to local after the first attempt.
D
Authentication will be attempted against the TACACS+ server without fallback because 'fallback-to-local' is not configured.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Authentication will use the local user database as a fallback.
When the TACACS+ server at 10.1.1.1 is unreachable, the switch will fall back to the local user database for authentication because the 'fallback-to-local' feature is enabled by default in Cisco IOS/IOS-XE for TACACS+ configurations. This behavior ensures that administrative access is not completely blocked if the remote AAA server becomes unavailable, allowing authentication against locally configured usernames and passwords.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✓
Authentication will use the local user database as a fallback.
Why this is correct
The 'local' keyword provides fallback.
Related concept
Read the scenario before looking for a memorised answer.
✗
Authentication will be denied immediately.
Why it's wrong here
There is a fallback to local authentication.
✗
Authentication will be attempted against the TACACS+ server repeatedly until timeout.
Why it's wrong here
It will fallback to local after the first attempt.
✗
Authentication will be attempted against the TACACS+ server without fallback because 'fallback-to-local' is not configured.
Why it's wrong here
The 'local' keyword enables fallback.
Common exam traps
Common exam trap: answer the scenario, not the keyword
Cisco often tests the misconception that 'fallback-to-local' must be explicitly configured for TACACS+ fallback to work, when in reality the fallback is determined by the order of methods in the AAA authentication command, and 'local' as a subsequent method provides the fallback automatically.
Trap categories for this question
Keyword trap
The 'local' keyword enables fallback.
Detailed technical explanation
How to think about this question
Under the hood, Cisco switches use the 'aaa authentication login default group tacacs+ local' command to define the authentication method list, where 'local' is the fallback method. The TACACS+ client on the switch sends an authentication request to the server; if no response is received (e.g., due to network unreachability or server timeout), the switch immediately moves to the next method in the list, which is the local database. This behavior is governed by the 'deadtime' and 'timeout' parameters but does not require explicit 'fallback-to-local' configuration because the method list order inherently defines the fallback sequence.
KKey Concepts to Remember
Read the scenario before looking for a memorised answer.
Find the constraint that changes the correct option.
Eliminate answers that are true in general but not in this case.
TExam Day Tips
→Watch for words such as best, first, most likely and least administrative effort.
→Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A junior network technician can log in to a core router but cannot reach the enable prompt or configuration mode. The AAA server is authenticating the login — but the authorisation policy only grants privilege level 1, not 15. Authentication (who you are) is working; authorisation (what you can do) is not.
What to study next
Got this wrong? Here's your next step.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Security — This question tests Security — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Authentication will use the local user database as a fallback. — When the TACACS+ server at 10.1.1.1 is unreachable, the switch will fall back to the local user database for authentication because the 'fallback-to-local' feature is enabled by default in Cisco IOS/IOS-XE for TACACS+ configurations. This behavior ensures that administrative access is not completely blocked if the remote AAA server becomes unavailable, allowing authentication against locally configured usernames and passwords.
What should I do if I get this 350-601 question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
About these practice questions
Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
This 350-601 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 350-601 exam.
Question Discussion
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
Sign in to join the discussion.