It should open a single connection with the exit node (TLS link) and use that link for multiple (as many as needed) circuits. So if there are two users using the same middle node and same exit simultaneously, the middle node should have one connection to the exit node (TLS link) with two different circuits wrapped inside.

I saw you mentioned that it can be found out, why not try to test it yourself and see if what I've said it's actually true in practice.

On 8/15/2016 6:48 PM, don.gould@tuta.io wrote:

Hello,

Do middle nodes create multiple connections to the same Exit node? (with different source port)

The reason I ask is because I am a little confused. Even the tor relay operators are completely honest and don't log anything, the ISP / upstream ISP could still log all the connections.

So they can see: [MiddleNode IP]:[Source Port] ==> [ExitNode IP]:[Dest Port (ORport)] -- Timestamp + Duration of connection.

So if I create a long running ssh connection that is going for 6 hours this will be unique to the middle node.

During this 6 hours, if another tor client chooses the same MiddleNode + ExitNode, does the MiddleNode create a new connection to the ExitNode? (Can be found out using netstat)

Or does it use the same connection that it already has established with the exit node?

Thanks.