How to disable the security policy with check point VPN-1 secure client?

Which version of the client is this? Versions later than R65 get increasingly difficult to control the security policy. And The 7x series will block incoming traffic no matter what.

You can do this from the command line with

scc sp off

However, this requires the usersc.c file to be changed, so that it contains:

api_manual_slan_control=true

But this may not work of course. My solution to this is to install the bastid thing into a VM and access it via the console.