This is the description of how Check Point used to modify Ethereal and called it CPEthereal, Ethereal has since moved on to become Wireshark.
To customize Wireshark to properly read and interpret FW Monitor files this is the way to do it:
From the Menu Edit choose Preferences, go to protocols Ethernet Select the ‘Attempt to interpret as Firewall-1 monitor file’ option
In the columns add a new column and name it Interface, from the possible fields choose “FW-1 monitor if/direction”
Now you will be able to properly read FW Monitor files but to make the result more readable you can also add some colorization rules by going to the View menu and choose the Coloring rules option
Add these new rules:
After creation move these rules to the top.
The result (this was a very old file capture on a Nokia):
Regards, Maarten.
This is just an excerpt from sk39510: How to configure Wireshark to display Check Point FireWall chains in an FW Monitor packet without referencing the sk and leaving out a lot of details. Also, you may need sk43076: How to work with large traffic capture files !