For nearly two years the Free Software Foundation has been fighting web crawlers (including many aggressively scraping training data for AI models). A botnet controlling about five million IPs hit one system for six months in 2025. Their systems administrator wrote this week that they view these as distributed denial-of-service attacks.

How are they fighting back?

We noticed patterns in the scrapers that were abnormal, which gave us material for writing regular expressions. Searching for the regular expression then gave us a large lists of IP addresses. Looking up the origin of those IP addresses revealed that some of the crawlers were using botnets of residential IP addresses to scrape ...