The tool exists to create a definition file for nftables from the fullbogons
files from Team Cymru. It can be used to filter out bogons
from incoming traffic with nftables.

There is probabily little advantage to this, but I wanted to play around with
named sets and so forth.

This is duct tape programming max. There are no tests and there is no plans
to add any. It’s for a very specific usecase I had and it’s not really going
to expand beyond this.

The intended usage is to be used in cron or systemd.timers, to generate a
definition file. The name of this file is the only argument to the program.
The file will be atomically replaced, so there should not be an instance of
a half written file, as long as rename is implemented atomically.

To make usage easier, I’ve included a systemd.timer file that will execute this
once every 4 hours roughly. This is how you can install it:

sudo install fullbogons-nftables-gen /usr/local/bin
sudo install -m644 contrib/systemd/fullbogons-nftables-gen.* /etc/systemd/system
sudo install -Dm644 contrib/nftables/example-refresh-set.nft /etc/nftables.d/refresh-fullbogons.nft

# This will fail, and that is ok, it is just to get the inital definitions file.
sudo systemctl start fullbogons-nftables-gen.service

# Then update /etc/nftables.conf with something akin to the content of
# contrib/nftables/example-ruleset.nft

# Then enable the timer
sudo systemctl enable --now fullbogons-nftables-gen.timer

I’ve also included two example nftables files. The first contrib/nftables/example-ruleset.nft
is an example usage of the defintions file. The second
contrib/nftables/example-refresh-set.nft is an example usage for hotswapping the
contents of the bogons sets, without reloading the whole ruleset.