We had a big wave of automated Mastodon signups with very predictable usernames.

I first tried the sledgehammer approach and blocked known VPN ranges at the firewall.

It (partially) worked.

It also blocked legitimate ProtonVPN users. 😬

So I replaced that with a tiny custom Mastodon validator that rejects the actual abusive username pattern instead.

Much cleaner: block the abuse, not the transport.

How-to + code:
https://gist.github.com/chofstede/a422427570004719196cde948521dd04

#Mastodon #Mastoadmin #Fediverse #SysAdmin #Ruby #Rails #Security @tux @AlienJay @aping