When a Tor hidden service is implemented it publishes an introductory point. To my current understanding, connections to the said hidden service is highly dependant on this introductory point.

  1. Is this introductory node jurst another Tor relay/exit node? Do I know that my Tor exit relay is somebody's introductory point? Can I host one introduction point if I want to?

  2. If the introductory service goes down, does it make the hidden service go down too? Is my hidden service smart enough to realise when the introductory point is down and republish another?

  1. Yes, it's a tor node which was elected for this role. You should host a node - it will become an introductory point one day. You can not forcible set the role and it's properties except the Exit, Bridge and Node(client-only mode disabled).

  2. Your service is smart enough and it will make the problem settled with the help of the rest of Tor network.

  • how does it inform the Tor network about its change of Introductory node? – Denis Jan 15 '17 at 11:47
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    via tor protocol communications: it's - roughly - an election process to find nodes that will be introductory point. So if the node goes down - it's polling/query result will be reflecting it's failed state, and the new election will be going on – Alexey Vesnin Jan 15 '17 at 23:34
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    No, the descriptor is updated to indicate that there are new introduction points and you pick 3 introduction points (by default), so if one goes down it won't affect the onion service. – cacahuatl Jan 16 '17 at 1:29

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