An application I work on works with Tor SOCKS5 and uses that to send HTTP 1.1 requests and receive HTTP responses.

It works great but from time to time it happens that instead of an HTTP response starting with HTTP status line a line containing single "?" (question mark as one character) is received instead.

Does anybody know what that actually mean? Does anybody know where in source code this "replying with '?' is"?

2 Answers 2


SOCKS is a different proxy protocol than HTTP. You can either use Tor's builtin HTTP proxy as a HTTP proxy or - using SOCKS5h - you need to make a pipe connection first and only after that step being successfully done you can go ahead with HTTP or HTTPS stuff through the pipe you created

  • We do the second option - i.e. we establish a TCP connection with Tor SOCK5 endpoint and then send an HTTP request through this connection. The issue I have described is that from time to time, we receive "?" instead of proper HTTP response through that Tor SOCKS5 TCP connection.
    – Centrury
    Oct 22, 2021 at 12:30
  • so - the SOCKS5s with DNS resolving through proxy reports tunnel creation, but you're getting the question mark? the hex code of the byte stream is matching the question mark? right?
    – Alexey Vesnin
    Oct 22, 2021 at 18:47
  • No, it was my mistake: tor.stackexchange.com/a/23061/32242.
    – Centrury
    Feb 23, 2022 at 7:12
  • OK, it's good to hear that you're fine afterwards!
    – Alexey Vesnin
    Feb 23, 2022 at 19:55

My bad the response was actually just end of stream and not "?" character.

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