Anti-bot system
Software that decides whether a request came from a human, using signals well beyond the IP address.
An anti-bot system evaluates incoming requests and decides whether to serve, challenge or block them. It usually runs as a reverse proxy in front of the application, which is why blocks arrive before the site’s own code executes.
#Signals it combines
- Network: the ASN, whether the range is hosting, its reputation history.
- Transport: TLS fingerprint, HTTP/2 settings, header order and casing.
- Behavioural: request rate, navigation order, timing regularity.
- Client-side: JavaScript execution, browser fingerprint, input events.
#Why changing IP alone rarely works
The address is one signal among many, and often not the decisive one. A request from a pristine residential address that presents a fingerprint no real browser produces is still identifiable. Consistency across all layers matters more than the quality of any single layer.
#How blocks present
Rarely as an honest error. Expect challenge pages, silent empty results, deliberately slow responses, or a 200 containing nothing useful. Detecting the block is often harder than avoiding it.