In this period a minor misconfiguration in the host of my vps produced an error when using some iptables parameters
iptables: Unknown error 4294967295
this error has a bug.
If we convert this number in hex we get:
so so actually we notice that that error is -1 in a 32 bit two's complement form.
So the first bug is that the kernel reports a negative error number to iptables, but iptables is able only to process positive numbers.
The error is produced because iptables ask to use a certain module (in my case ipt_state) and the kernel doesn't have that module loaded, but, instead of reporting a specific error for that issue, it just produces a generic -1.
The first (the negative/positive) issue is a bug, the other is just an unproperly reported error condition, the "missing module" condition should have a specific error code so that the issue can be easily identified an solved.