At 03:20 3/23/2018 +0000, tor <[email protected]> wrote:
>> Suggestion: DoSCircuitCreationMinConnections=1 be established in consensus
>
>The man page for the above option says:
>
>"Minimum threshold of concurrent connections before a client address can be 
>flagged as executing a circuit creation DoS. In other words, once a client 
>address reaches the circuit rate and has a 
>minimum of NUM concurrent connections, a detection is positive. "0" means use 
>the consensus parameter. If not defined in the consensus, the value is 3. 
>(Default: 0)"
[snip]
>
>Am I misunderstanding?

"concurrent connections" refers to concurrent TCP+TLS network layer 
connections, not to Tor circuits--nominally one-connection-per-peer IP.  It 
means the excess circuit-extend rate logic does not kick in at all until at 
least N TCP connections from a particular IP exist.  Once the configured number 
of TCP connections is present, the circuit extend rate is examined.

An adversary who stays under the configured limit (presently three) can extend 
circuits at extreme rates on (two) TCP connections.  Adversary must marshal a 
larger number of IP addresses than previously to obtain the same effect and 
this raises the cost of attack, but they may still cause significant trouble as 
my relay's statistics demonstrate.

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