Operating system for cooking programs?

Question

Network administration

ables -M OUT OP
abes --sh
abes --in
ables -QT -e -r wj
ables -QT -e -0 wj
ables -CT -t T -j uoyy

Answer 1

Deny any network activity through iptables, leave permission only for connecting to vpn, well, do not block vpn at all.

Answer 2

Ideal:
Make two virtual machines, in one something like a gateway, for example pfsense, raise vpn in it and give it access to the network, and allow the second to go to the network only through this virtual machine

Answer 3

dnscrypt