tor-ctrl-observer - Tor Connection Destination Viewer

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Ever wanted to know which information is sent by an application? tor-ctrl-observer shows connection information of applications using Tor.

What tor-ctrl-observer is[edit]

Ever wanted to know which information is sent by an application? tor-ctrl-observer shows connection information of applications using Tor.

Sample printout:

250-stream-status=1094 SENTCONNECT 20
250-stream-status=1094 SUCCEEDED 20

tor-ctrl-observer is especially useful in combination with Whonix because:
All traffic originating from Whonix-Workstation and Whonix-Gateway is routed over Tor. [1] [2] [3] [4] [5] [6] [7]

tor-ctrl-observer operates in sane, secure way by using Tor's control protocol to make information visible to users that Tor is internally processing and ready to share with users on request anyhow.

tor-ctrl-observer Advantages[edit]


In Whonix-Gateway.

1. Open a terminal.

2. Run tor-ctrl-observer.


3. Terminate tor-ctrl-observer with signal sigint.

Press keyboard keys Ctrl + C.

What tor-ctrl-observer is not[edit]

tor-ctrl-observer does not attempt to be, is not and cannot be a:

  • Network level leak tests replacement: In illustrative language, this is because tor-ctrl-observer does only nicely ask Tor "please show me all the connections you are creating". It is then up to Tor to honor the request. Tor might generally do so but if there were bugs in the Tor control protocol then tor-ctrl-observer could not catch these. If connections are by-passing Tor, in other words not using Tor then Tor is obviously not aware of these connections and therefore tor-ctrl-observer cannot observe such connections.
  • Tor auditor: For the same reason as above, tor-ctrl-observer cannot be expected to find bugs in Tor.
  • Tor Controller: Such as Nyx. What is the difference between nyx and tor-ctrl-observer? nyx shows information about which Tor circuits (Bridges, Tor Entry Guards, Tor middle or exit relays) are used but not the final connection destinations. On the other hand, tor-ctrl-observer shows information about final connection destinations.

Forum Discussion[edit]

See Also[edit]


  1. Starting from Whonix version 0.2.1, traffic from Whonix-Gateway is also routed over Tor. This approach conceals the use of Whonix from entities monitoring the network.
  2. For preserving the anonymity of a user's Whonix-Workstation activities, it isn't essential to route Whonix-Gateway's own traffic through Tor.
  3. For those interested: Altering DNS settings on Whonix-Gateway in /etc/resolv.conf only impacts DNS requests made by Whonix-Gateway's applications that utilize the system's default DNS resolver. By default, no applications on Whonix-Gateway that generate network traffic utilize this default resolver. All default applications on Whonix-Gateway that produce network traffic (like apt,, sdwdate) are explicitly configured, or force by uwt wrappers, to use their dedicated Tor SocksPort (refer to Stream Isolation).
  4. Whonix-Workstation's default applications are configured to use dedicated Tor SocksPorts (see Stream Isolation), avoiding the system's default DNS resolver. Any applications in Whonix-Workstation not set up for stream isolation - such as nslookup - will employ the default DNS server configured in Whonix-Workstation (through /etc/network/interfaces), which points to Whonix-Gateway. These DNS requests are then redirected to Tor's DnsPort by the Whonix-Gateway firewall. Changes in Whonix-Gateway's /etc/resolv.conf don't influence Whonix-Workstation's DNS queries.
  5. Traffic produced by the Tor process, which by Debian's default operates under the user debian-tor originating from Whonix-Gateway, can access the internet directly. This is permitted because Linux user account debian-tor is exempted in the Whonix-Gateway Firewall and allowed to use the "regular" internet.
  6. Tor version (with no changes announced at the time of writing), the Tor software predominantly relies on TCP traffic. For further details, see Tor wiki page, chapter UDP. For DNS, please refer to the next footnote.
  7. Tor doesn't depend on, nor uses a functional (system) DNS for most of its operations. IP addresses of Tor directory authorities are hardcoded in the Tor software by Tor developers. Exceptions are:
    • Proxy settings that use proxies with domain names instead of IP addresses.
    • Some Tor pluggable transports such as meek lite, which resolves domains set in url= and front= to IP addresses or snowflake's -front.

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