The command fw ctl zdebug + drop is the most direct and efficient method for viewing all dropped packets in real time. It is a kernel debugging tool that instructs the firewall kernel to print a debug message to the console for every packet it drops. This process occurs at the lowest level, providing immediate output without the latency or overhead associated with the standard logging daemon (fwd) writing to a log file (fw.log). This makes it the superior choice for real-time, low-level analysis.

A. tail -f $FWDIR/log/fw.log |grep drop reads from a file. This introduces a delay as the log daemon must first process and write the event, making it less "real-time" than a direct kernel debug.

B. cat /dev/fw1/log dumps a raw, unfiltered stream of all kernel log data. It is not specific to dropped packets and is difficult to interpret, making it inefficient for this task.

D. Smartlog is a GUI-based application within SmartConsole. It is not a command-line tool and is inherently less simple and efficient for immediate, real-time troubleshooting at the gateway level.

1. Check Point SecureKnowledge Article sk32553: "How to use 'fw ctl zdebug' command". This document explicitly describes the command's function: "fw ctl zdebug + drop - shows all packets that are dropped by the firewall". It details how zdebug provides real-time kernel debug messages.

2. Check Point R81.10 CLI Reference Guide: In the chapter on "Firewall Control Protocol Commands", the fw ctl zdebug command is detailed as a mechanism for printing debug messages from the Firewall kernel. This confirms its role as a low-level, real-time diagnostic tool, distinct from higher-level logging.

3. Check Point Certified Security Expert (CCSE) R81.10 Study Guide: The advanced troubleshooting sections of official courseware differentiate between log-based analysis (Smartlog, fw.log) and kernel-level debugging (fw ctl zdebug, fw monitor). The guide positions fw ctl zdebug as the tool for observing kernel-level packet handling decisions, such as drops, in real time.