Debug IP Packet Timestamps Configuration on R4
Short answer
D Service timestamps debug datetime msec show-timezone adds UTC-based timestamps to debug ip packet output, independent of R4's local time zone.
Question
Key Takeaways
This question tests the distinction between log and debug timestamp commands and the time zone behavior of localtime versus default UTC. A common trap is choosing the log variant or assuming local time is time-zone independent.
When debug ip packet output on R4 lacks timestamps, the correct fix is to enable debug timestamps with service timestamps debug datetime msec show-timezone. This configuration uses UTC and displays the time zone, ensuring event times are comparable regardless of R4's local time zone.
Common mistake: Many learners pick service timestamps debug datetime msec localtime (B) because they focus on 'debug' but overlook that localtime makes timestamps depend on R4's time zone, while the question explicitly asks for time-zone-independent timestamps.
Expert Analysis
Why the Answer Is Correct
The engineer is troubleshooting debug ip packet output, which is a debug message stream, so timestamps must be enabled with the debug keyword in the service timestamps command. The phrase "regardless of the time zone" means the timestamp should not depend on R4's local time zone; omitting the localtime keyword makes IOS use UTC, which is the same absolute time across all devices. Option D adds show-timezone, which explicitly appends the time zone name (UTC) to each debug line, so events can be accurately correlated. Option B uses localtime, which would display timestamps in R4's configured time zone, violating the requirement. Therefore, service timestamps debug datetime msec show-timezone is the correct configuration.
Why the Other Options Are Wrong
Options A and C use the log keyword, which controls timestamps on syslog/logging messages, not on debug output like debug ip packet. They would leave the debug messages untimestamped. Option B configures the correct debug stream but relies on localtime, so timestamps reflect R4's local time zone and will differ if the device's time zone changes or is misconfigured; it also omits show-timezone, leaving the time zone ambiguous. Option D avoids these pitfalls by using UTC and displaying the zone. The community comment from Pietjeplukgeluk that "you cannot set the msec command without using datetime first" is a misunderstanding because D includes both datetime and msec.
Community Comment Notes
Learners are split: some read "regardless of the time zone" as "do not show the time zone," as IntangibleW posted, which led them to B. However, dapardo pointed out that the exhibit likely already has service timestamps log datetime msec applied, so the debug command should match that UTC-based format rather than introduce localtime. kldoyle97 argued that "we want the time displayed in UTC not local time," which aligns with D. Pietjeplukgeluk's objection about msec is factually incorrect because both keywords are compatible. The consensus for D is based on the time-zone-independent requirement.
Exam Strategy
When you see a missing-timestamp scenario, first check whether the output is debug or log. Then decide if the time must be time-zone independent; if so, avoid localtime and use show-timezone to display UTC.
Frequently Asked Questions
Why is service timestamps log datetime msec not the right fix for missing debug timestamps?
Does show-timezone without localtime display UTC?
Community Votes
57% of anonymous learners picked answer B. Votes are pick records left by other test-takers — they are not the verified answer.
Discussion 7 contributions
Compiled from public community threads and reader submissions, lightly edited for clarity. Handles and vote tallies are shown as recorded, and comments reflect the views of individual contributors.
From public community threads 7
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dapardo 👍 3 Answered DAgree on this since service timestamps log datetime msec is already applied in the configuration, the next step is to put service timestamps debug datetime msec. First step - log messages timestamp Second step - Debug messages timestamp By doing this all logs and debug messages will include timestamps.
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kldoyle97 👍 2 Answered DGoing to go with the provided answer on this. service timestamps debug datetime msec show-timezone Question states: "regardless of timezone" I am assuming that means we want the time displayed in UTC not local time choice B has 'local-time' configured, and that is not want we want
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krobo 👍 2 Answered BThe following example enables time stamps on logging messages, showing the current time and date relative to the local time zone, with the time zone name included: service timestamps log datetime localtime show-timezone
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Pietjeplukgeluk 👍 2 Answered BB == correct. Note D is wrong cause you cannot set the msec command without using datetime first. WAN(config)#service timestamps debug ? datetime Timestamp with date and time uptime Timestamp with system uptime <cr>
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IntangibleW 👍 2 Answered B"regardless of the time zone" = do not show time zone
Show 2 more comments
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wwwwaaaa 👍 1 Answered DThis reminds me of this question: Question #171 Topic 1 A network engineer is investigating a flapping (up/down) interface issue on a core switch that is synchronized to an NTP server. Log output currently does not show the time of the flap. Which command allows the logging on the switch to show the time of the flap according to the clock on the device? A. service timestamps log uptime B. clock summer-time mst recurring 2 Sunday mar 2:00 1 Sunday nov 2:00 C. service timestamps log datetime localtime show-timezone D. clock calendar-valid Correct Answer: C For that I might go with D TBH
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assotchet 👍 1for me the good answer is B one must pay attention to regardless of time zone in the question
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