During firewall kernel debug with fw ctl zdebug you received less information that expected. You noticed that a lot of messages were lost since the time the debug was started. What should you do to…

Question

Options

• AIncrease debug buffer; Use fw ctl debug -buf 32768
• BRedirect debug output to file; Use fw ctl debug -o ./debug.elg
• CRedirect debug output to file; Use fw ctl zdebug -o ./debug.elg
• DIncrease debug buffer; Use fw ctl zdebug -buf 32768

• A
  81% (29)
• B
  3% (1)
• C
  11% (4)
• D
  6% (2)

Explanation

When debug messages are lost during fw ctl zdebug, it indicates the kernel debug buffer is too small and overflowing - the fix is to increase it using fw ctl debug -buf 32768, which allocates a larger buffer (in KB) before the debug session captures all messages without dropping them.

Why the distractors are wrong:

• B misidentifies the problem as an output issue rather than a buffer issue, and fw ctl debug -o is not a valid flag for redirecting output.
• C correctly suggests file redirection as a concept, but fw ctl zdebug does not accept a -o flag - this is a fabricated syntax.
• D identifies the right concept (increase buffer) but uses the wrong command - fw ctl zdebug does not accept -buf; only fw ctl debug does.

Memory tip: Think of the two commands as having separate roles - fw ctl debug configures the debug environment (flags, buffer size), while fw ctl zdebug reads from it. Buffer tuning always belongs to fw ctl debug, never zdebug.

No community discussion yet for this question.