CCTE book p.279 If the -m is not included, the debug defaults to the Firewall module. By running the fw ctl debug -help command, you can find the description of the -m flag and the list of modules CCTE book p.281 Althought fw ctl zdebug is quick and easy to use, it has some limitations: for example - it allocate enables a 1 MB buffer. - it does not let users allocate buffer. - it does not let users enabel timestamps or define the type and frequency of treshholds.

Answer A is wrong, according to https://support.checkpoint.com/results/sk/sk100808: fw ctl zdebug + <flags> where <flags> could be any fw module flag. "Note that fw ctl zdebug runs a kernel debug (Answer C!). It is a shorthand way of defaulting all kernel parameters, setting the buffer to 1MB (Answer D!), and then adding fw module flags. Pressing CTRL+C will terminate the process and return all debugging flags to default." So answer B is the answer they are looking for. Though I'm quite sure fw ctl zdebug does clean the buffer, too?

To debug additional modules, fw ctl debug is needed. With fw ctl zdebug, you are able to additional debug flags only.

The buffer is way too limited for live production. This means that lots of messages might be just lost because buffers does not have enough room to hold them before read. Regarding debugging additional modules, zdebug supports several debug flags... http://downloads.checkpoint.com/dc/download.htm?ID=56864

A because it's the best available answer. Not to be able to choose a module is definitely not a benefit. That it automatically allocates 1MB buffer is better then the default 50KB. It is not a benefit that you are not able to choose a greater buffer but if you look for all anwers, A ist the best

Details and Limitations Although fw ctl zdebug is quick and easy to use, it has limitations that may prevent the thorough analysis of an issue. For example, the command automatically enables a 1 MB buffer. It does not allow users to allocate a buffer. In addition, it does not allow users to enable timestamps or define the type and frequency of thresholds.