156-587-R81-20 practice question 23 of 25

After kernel debug with “fw ctl debug you received a huge amount of information It was saved in a very large file that is difficult to open and analyze with standard text editors Suggest a solution to solve this issue

Full set: 109 questions
Answer options
A: Reduce debug buffer to 1024KB and run debug for several times
B: Use Check Point InfoView utility to analyze debug output
C: Use “fw ctl zdebug because of 1024KB buffer size
D: Divide debug information into smaller files. Use “ fw ctl kdebug -f -o “filename -m 25 - s ‘’1024’’ Correct answer
Correct Answer:
D. Divide debug information into smaller files. Use “ fw ctl kdebug -f -o “filename -m 25 - s ‘’1024’’
Explanation

The problem describes a scenario where a kernel debug output file is too large to be opened by standard text editors. The fw ctl kdebug command is the appropriate tool for processing kernel debug information. The -f flag allows reading the debug data from a pre-existing file. The -o, -m (max files), and -s (size in KB) flags provide the functionality to split the large input file into multiple smaller, more manageable output files. This directly addresses the issue of being unable to analyze the huge file, allowing the examiner to review the data in smaller chunks.

Why Incorrect

A. Reducing the buffer size and re-running the debug alters the data collection method for future captures; it does not help analyze the existing large file and risks missing crucial information.
B. Check Point InfoView is a legacy log viewer designed for analyzing formatted log files from SmartView Tracker, not for parsing the raw, unstructured text output of a kernel debug.
C. The fw ctl zdebug command is used to clear (zero out) the kernel debug buffer. It erases debug data and does not provide any analysis or file processing capabilities.

References

1. Check Point R81.20 CLI Reference Guide, Page 318, "fw ctl kdebug". The guide details the command syntax and flags. It specifies:

-f : "Read debug buffer from instead of from the kernel."

-o : "Write output to instead of stdout."

-s : "Split output file to chunks of KB."

-m : "Maximum number of split output files."

This documentation directly confirms that the command in option D is the correct method for processing and splitting a large, saved debug file.

2. Check Point Support Center, SK Article sk84420: "How to run kernel debug on Security Gateway". This article, in the section "Reading the debug buffer", explains the use of fw ctl kdebug to dump the buffer. While it focuses on live capture, the principles of using fw ctl kdebug as the primary tool for handling debug buffer data are established here. The splitting functionality is an advanced feature of this core utility.

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