In my answer to How do I setup Tor on Debian for secure use as a SOCKS5 proxy?, I don't force traffic to port 123 (NTP) to use Tor. Being UDP, I don't get how I can.

Is there an "NTP port" for Tor? I don't see anything in the manual.

What is the recommended way for handling NTP?


Your best bet is using tlsdate. This software connects to some TLS servers and extracts the time from the handshake. tlsdate uses TCP, so it can be used with Tor. As far as I know ChromeOS uses tlsdate to securely retrieve time data.

  • 1
    Tails does not use tlsdate. See Time syncing design document
    – Lunar
    Aug 5 '14 at 9:01
  • 2
    @Lunar Could you perhaps make that an answer? Once I understand and test, I could also do that.
    – mirimir
    Aug 5 '14 at 18:30
  • @Lunar OK, that seems pretty straightforward. There's a custom HTP, and a Network Manager script. Once I test, would you prefer that I quote rather than paraphrase?
    – mirimir
    Aug 5 '14 at 18:36
  • @mirmir Do what feels appropriate. :) Don't forget to talk to Tails folks if you work on extracting their htpdate system. I guess other distributions might be interested in re-using them.
    – Lunar
    Aug 6 '14 at 10:45
  • I forgot about this. Upon reflection, I'm dubious about relying on HTTP/S headers for time. So is there no way to poll any NTP servers?
    – mirimir
    Oct 6 '14 at 7:38

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