Thank you! There’s also a blog post, Classifying Data Center IP Addresses in Phoenix Web Applications with Radix Trees, to go with the talk.

What about Bloom Filters?

Many IP address lookup approaches employ Bloom filters to obtain a high-speed search performance. Especially, the search performance of trie-based algorithms can be significantly improved by adding Bloom filters, because Bloom filters can determine whether a node exists in a trie without accessing the trie. The false positive rate of a Bloom filter must be reduced to enhance the lookup performance. One important characteristic of a trie is that all the ancestors of a node are also stored. The proposed IP lookup algorithm utilizes this characteristic in reducing the false positive rate of a Bloom filter without increasing the Bloom filter size.

Bloom Filter is memory efficient than a Hash Map with the same performance. The only thing to note is that this is a probabilistic data structure so for a small number of cases, it may give wrong results (which can be limited).

The applications of Bloom Filter are:

• Weak password detection
• Internet Cache Protocol
• Safe browsing in Google Chrome
• Wallet synchronization in Bitcoin
• Hash based IP Traceback
• Cyber security like virus scanning

Bloom Filters by Example

Some Elixir Libs: Blex && Bloomex

P.S. For blocking some more bots, we can use ua_inspector & device-detector:
https://github.com/matomo-org/device-detector
https://github.com/elixir-inspector/ua_inspector

Very interesting!

During my time at Papa we just banned India and China IPs as a whole and that solved the vast majority of our problems with bots.

If you’re a startup I highly recommend going that route (at least initially) since it’s cheap and easy. Just make sure you don’t actually do business with the users in those countries. Use common sense