What is the limit and is it configurable? I am connecting via Polipo SOCKS5 proxy.

Edit: I'm asking because I see a lot of 504s when I go for multiple simultaneous requests.

  • Depends how you look at it. 1 is normally what you'll see, because everything is going over a single TLS connection to your guard. Inside of that TLS connection multiple circuits are negotiated. Inside of those circuits multiple streams are negotiated. You'll need to clarify the question.
    – cacahuatl
    Oct 21, 2016 at 3:16
  • @canonizingironize I was thinking about regularly polling a few onions for updates and so in my current setup there would be multiple requests going out concurrently as a batch. Each request would be to a different onion domain. Would that be permissible by the client or is 1 the max in this regard? Oct 21, 2016 at 8:21
  • Each onion connection is a distinct circuit (and infact, can be up to 3 circuits, RP, HSDir, IP) There's probably some hard limit (like a few million till you exhaust circuit IDs?) from the tor software/protocol. You're far more likely to hit limits of network capacity, CPU capacity, killing your guard. Polipo probably has similar issues. You'll need to engineer a smoother solution that whatever jank you've duct-taped together.
    – cacahuatl
    Oct 21, 2016 at 9:12
  • What make you think it's duck taped together? Oct 21, 2016 at 20:34
  • The fact that it's failing and you've no idea why and "Polipo" is in the chain for some reason (probably because what ever is behind polipo doesn't know how to speak SOCKS, because if it does speak SOCKS then you're doing it wrong)
    – cacahuatl
    Oct 21, 2016 at 20:45

1 Answer 1


It seems that 504 bad gateways is a common problem with onions no longer with us. I guess a 404 would only happen when the page is offline but the site's server is still up in some form.

  • 504 is an HTTP error, probably related to Polipo.
    – cacahuatl
    Oct 23, 2016 at 18:23
  • And you guess this 'probably' based on what information supplied? Oct 23, 2016 at 21:24
  • Well, it's either A) the connection is fine and it's the backend on the .onion in which case it's not a Tor related problem or B) it's polipo and it might be related to interaction between polipo and Tor. Those are the only two places that HTTP comes into it. If B the HTTP error message is an abtraction of some other issue, you should determine where it is coming from, the onion service, or polipo, then investigate there.
    – cacahuatl
    Oct 23, 2016 at 21:29
  • Astonishing lack of awareness. I've already explained in my own answer the onions in question are offline. Yet you comment in line (!) telling me the problem 'probably' lies in Polipo! Oct 24, 2016 at 0:00

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