[tor-relays] Is Tor-network protected from using one hop?

[teor]

> On 27 Jun 2018, at 00:34, Matt Traudt <pastly at torproject.org> wrote:
> 
>> On 6/26/18 10:29, Nagaev Boris wrote:
>>> On Tue, Jun 26, 2018 at 5:27 PM, Matt Traudt <pastly at torproject.org> wrote:
>>>> On 6/26/18 10:16, dave levi wrote:
>>>> I'm testing few things in Tor and I noticed that if im changing(from the
>>>> source code) the number of hop's(nodes) to be more then 3 hop's it
>>>> work's fine(slowly,  but still working) and if im sting only 2 hop's its
>>>> still works great. but, when i'm setting only 1 hop, i can open the
>>>> Tor-browser but i can't use it(Tor-browser) to visit site(regular site
>>>> or onion site too). so im thinking maybe the Tor-network have protected
>>>> from users who are using 1 hop?
>>>> 
>>> 
>>> Yes.
>>> 
>>> Even before the DoS mitigation stuff, relays wouldn't allow themselves
>>> to be used as the only hop in a circuit. Apparently this affects onion
>>> service circuits too.
>>> 
>>> If you want a single-hop proxy, then you don't want Tor.
>> 
>> How does a relay know if there is another relay in the circuit? What
>> if the attacker runs a "relay" locally?
>> 
> 
> The way a client connects to a relay and the way a relay connects to
> another relay is different.
> 
> Technically the attacker/user could run a relay/bridge locally and

A relay, not a bridge: bridges look like clients to relays.
Also, relays that aren't in the consensus trigger the exit defence,
and I think they trigger some of the DDoS defences as well.

> connect to that before the remote relay, creating a 2-hop circuit that
> **might** have performance similar to a 1-hop circuit.

T