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What Is Tor? How BotBlocker Detects and Blocks Connections from the Tor Network

The Tor network (The Onion Router) is a global system designed to provide privacy and anonymity online. While Tor is a crucial tool for activists, journalists, and those under surveillance, it’s also widely abused by attackers and bots to hide their identity and bypass security restrictions.

How Does Tor Work?

Tor routes user traffic through a series of volunteer-operated servers (called “nodes” or “relays”), encrypting the data at every step. This makes it extremely difficult to trace the origin of a connection—websites see only the IP address of the last “exit node,” not the real user.

Key features:

  • Anonymity: Real IP addresses are completely hidden
  • Global: Thousands of nodes worldwide
  • Bypass censorship and blocks: Users can reach restricted sites

Why Is Tor a Security Risk for Websites?

  • Abuse and attacks: Tor is often used for scraping, brute-force attacks, spam, and fraud, because attackers can rotate exit nodes and avoid IP bans.
  • Low traceability: Blocking or blacklisting one exit node is ineffective; new nodes appear constantly.
  • Bypassing geoblocking and access controls: Tor allows anyone to appear from almost any country.

How BotBlocker Detects and Blocks Tor Connections

Detection

  • IP checks: BotBlocker compares incoming visitor IP addresses against regularly updated lists of Tor exit nodes.
  • Behavioral analysis: Combined with other signals (empty User-Agent, suspicious headers, proxy/VPN usage) for higher accuracy.
  • Automatic updates: The plugin fetches new lists to keep detection up to date, reducing false negatives.

Blocking

  • Out-of-the-box: BotBlocker can immediately block or challenge all connections from Tor exit nodes—no manual configuration needed.
  • Configurable: Admins can choose whether to block, show a captcha, or only log Tor connections, depending on their project’s needs.

Why Block Tor Connections?

  • Reduces automated attacks and abuse: Most real users do not access sites via Tor.
  • Prevents brute force and scraping: Attackers can’t simply rotate IPs to bypass bans.
  • Protects sensitive actions: Prevents anonymous registrations, voting, or content scraping.

When to Allow Tor?

  • Human rights and privacy projects: If your site serves activists, journalists, or people in repressive regions, you might want to allow Tor and use softer checks instead of full blocking.

FAQ

Will blocking Tor hurt real users?
For most commercial, business, or blog sites—no. But if you have a sensitive audience, consider soft restrictions (captcha, logging) instead.

Does Tor detection slow down my site?
No, BotBlocker uses optimized lookup tables for instant detection.

Is the Tor list always up to date?
Yes, BotBlocker automatically updates the Tor exit node database.

Read about all BotBlocker detection features

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