Open source works just fine for this - take a look at geoacumen-country

https://github.com/geoacumen/geoacumen-country

Isn’t that only countries though? They were talking about detecting VPS

I work for IPinfo. We offer IPinfo Lite for free. With a little bit of time in identifying the ASNs, you can implement a decent way to block a good number of bots fairly easily using the free data alone.

Good to know, thank you. Would you do this by fully blocking particular ASNs? Or something more granular?

You can block entire ASNs. If you are frustrated with bots, blocking Tencent's entire IP address space would have very few downsides.

If you have fail2ban or NGINX logs, you can use our CLI to summarize those IPs and identify the ASNs you want to block. But before you block entire ASNs, make sure they are not classified as "ISP" type. For that, visit our website's ASN page first.

I have quite a few community posts around this approach. https://community.ipinfo.io/

If you have raw logs, you can send them to me as well, and I can review them and provide some guidance.

Appreciate it, I'll check out your posts.

Focsec.com IP database for offline use (datacenters, VPNs, proxies, bots) runs around $1k/month for internal-only use.

You don't need to spend anywhere near $40k a year to get that info... You don't even need to spend $1

What's your strategy?

See my comment in the parent - there are cheaper options, don't use maxmind!