Cloudflare and websites that use Cloudflare can block users through several methods.
- IP blocking: Cloudflare allows website owners to block specific IP addresses or ranges of IP addresses.
- Country blocking: Website owners can use the platform to stop traffic from entire countries or regions. This is a form of geofencing/geoblocking.
- Firewall rules: Cloudflare’s Web Application Firewall (WAF) can be configured to block users based on various criteria. Suspicious behavior or specific request patterns are common criteria.
- Challenge pages: Cloudflare refers to CAPTCHA screens and other verification methods to suspicious traffic as “Challenges.” These can effectively block automated attacks or crawlers. (Real human users shouldn’t encounter these problems unless there is a glitch with the page)
- Rate limiting: Cloudflare can limit the number of requests from a single IP address. It may block blocking users who exceed these limits.
- Browser integrity checks: Cloudflare can block requests from browsers that don’t meet certain criteria or appear to be malicious.
- Threat intelligence: Cloudflare may automatically block IPs known to be associated with malicious activity.
- Custom blocking rules: Website owners who use Cloudflare can create custom rules to block specific types of traffic or users.
Being blocked by Cloudflare doesn’t necessarily mean being blocked from the entire internet. It typically means being blocked from accessing specific websites or services that use Cloudflare’s protection.