@bimmer @mcdanlj however, you can use the tools documented by @alex ¹ ² to dynamically grab the IPs currently owned by an ASN and shovel that info directly into your firewall.
¹: https://social.alexschroeder.ch/@alex/statuses/01K54J70TVE946JKARGQJ3JJGM
Oct 4, 2026, 2:29 PM@gnomon @bimmer @mcdanlj If you feel like looking at some scripts, they are collected here: https://alexschroeder.ch/admin/
Some of them, like asn-find, are Python scripts using the pyasn library. You get to download an updates database for local use every now and then, mapping ASN to IP address ranges and so.
asn.fish uses dig and a DNs lookup.
asn-ban.fish is how I add things to fail2ban jails and all that.
In any case, a place to dig in. Happy to answer questions. 😄