Question regarding logging for remotely managed Gateway used for S2S VPN

[HansKazan]

Hello CheckMates

I have to establish a VPN S2S tunnel with a remotely managed CP-GW. To prepare, I have simulated the environment in my lab (R81.20 JHF 84) and noticed that no amount of NAT or packet manipulation let my "on-prem" SMS receive the logging originating from the VPN-GW.

After following this sk, it worked.
https://support.checkpoint.com/results/sk/sk111954

This leads me to the following questions below.

• Could someone please elaborate how and why this works on a technical level and if a more modern approach exists that I may have overlooked if the modern answer deviates from what is written in the sk?
• Additionally, what change or impact does this change to the implied_rules.def file have for the locally managed CP Gateways? How does the functionality of log connections change, if at all, and what steps should then be taken.
• Furthermore, why does port:257 not show up in the logging after the connection between the VPN-GW and SMS is established? Is it encapsulated in another protocol?

Thank you for your valuable time and input as always!