Tor Network Primer For Tordex Users And Researchers

Quick answer: what do you need to know about Tor?

Tor routes connections through several relays so that no single relay sees both who is communicating and what is being communicated. Onion services use that network to publish a server without a public IP address or a conventional domain.

Tor in one paragraph

A client builds a circuit through relays. Each relay knows only the previous and next hop. This limits what any one relay can see and makes network-level surveillance harder. It does not make a user invisible, and it does not make content trustworthy.

How an onion service is addressed

The address is derived from cryptographic material rather than registered with a registrar. That is why it is long and why a single character change points somewhere else. The address both locates the service and helps the client authenticate it.

What the client and service each know

The client knows the address it is trying to reach. The service learns that someone connected, but not necessarily who. Both sides rely on the anonymity properties of the network, and both can weaken those properties through behaviour, configuration, or metadata.

Why publishing an onion service is different

An operator can run a server without exposing a public address. The Tor software generates the onion address and manages introduction points. The operator still has to decide who may find the service, what it serves, and how it handles abuse and load.

Where search fits

Search engines are not part of Tor itself. They are separate crawlers that try to discover and index onion pages. That is why an index can miss services that are perfectly reachable, and why a search result is not a network-level fact.

Common misconceptions

• Tor makes you anonymous. It provides transport anonymity, not invisibility from your own behaviour or browser.
• Onion services are all illegal. The network hosts a wide range of material, including legitimate privacy and research tools.
• A search index is the network. It is a partial catalogue built by a crawler.

What to read next

Read how the Tordex index is built or return to the Tordex overview.

Last updated: October 2026. Site map.