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TOR Support In Bulwark

It is possible to run Bulwark as a Tor hidden service, and connect to such services.

The following directions assume you have a Tor proxy running on port 9050. Many distributions default to having a SOCKS proxy listening on port 9050, but others may not. In particular, the Tor Browser Bundle defaults to listening on a random port. See Tor Project FAQ:TBBSocksPort for how to properly configure Tor.

Run Bulwark behind a Tor proxy

The first step is running Bulwark behind a Tor proxy. This will already make all outgoing connections be anonymized, but more is possible.

-proxy=ip:port  Set the proxy server. If SOCKS5 is selected (default), this proxy
                server will be used to try to reach .onion addresses as well.

-onion=ip:port  Set the proxy server to use for tor hidden services. You do not
                need to set this if it's the same as -proxy. You can use -noonion
                to explicitly disable access to hidden service.

-listen         When using -proxy, listening is disabled by default. If you want
                to run a hidden service (see next section), you'll need to enable
                it explicitly.

-connect=X      When behind a Tor proxy, you can specify .onion addresses instead
-addnode=X      of IP addresses or hostnames in these parameters. It requires
-seednode=X     SOCKS5. In Tor mode, such addresses can also be exchanged with
                other P2P nodes.

-onlynet=tor    Only connect to .onion nodes and drop IPv4/6 connections.

An example how to start the client if the Tor proxy is running on local host on port 9050 and only allows .onion nodes to connect:

./bulwarkd -onion= -onlynet=tor -listen=0 -addnode=FIXME_ADDRESS_TOR

In a typical situation, this suffices to run behind a Tor proxy:

./bulwarkd -proxy=

Run a Bulwark hidden server

If you configure your Tor system accordingly, it is possible to make your node also reachable from the Tor network. Add these lines to your /etc/tor/torrc (or equivalent config file):

    ClientOnly 1
    SOCKSPort 9050
    SOCKSPolicy accept
    Log notice file /var/log/tor/notices.log
    ControlPort 9051
    HiddenServiceDir /var/lib/tor/bulwark/
    HiddenServicePort 989
    HiddenServiceStatistics 0
    ORPort 9001
    LongLivedPorts 989
    ExitPolicy reject *:*
    DisableDebuggerAttachment 0
    NumEntryGuards 8

The directory can be different of course, but (both) port numbers should be equal to your bulwarkd's P2P listen port (52541 by default).

-externalip=X   You can tell bulwark about its publicly reachable address using
                this option, and this can be a .onion address. Given the above
                configuration, you can find your onion address in
                /var/lib/tor/bulwark-service/hostname. Onion addresses are given
                preference for your node to advertize itself with, for connections
                coming from unroutable addresses (such as, where the
                Tor proxy typically runs).

-listen         You'll need to enable listening for incoming connections, as this
                is off by default behind a proxy.

-discover       When -externalip is specified, no attempt is made to discover local
                IPv4 or IPv6 addresses. If you want to run a dual stack, reachable
                from both Tor and IPv4 (or IPv6), you'll need to either pass your
                other addresses using -externalip, or explicitly enable -discover.
                Note that both addresses of a dual-stack system may be easily
                linkable using traffic analysis.

In a typical situation, where you're only reachable via Tor, this should suffice:

./bulwarkd -proxy= -externalip=FIXME_ADDRESS_TOR -listen

(obviously, replace the Onion address with your own). If you don't care too much about hiding your node, and want to be reachable on IPv4 as well, additionally specify:

./bulwarkd ... -discover

and open port 51472 on your firewall (or use -upnp).

If you only want to use Tor to reach onion addresses, but not use it as a proxy for normal IPv4/IPv6 communication, use:

./bulwarkd -onion= -externalip=FIXME_ADDRESS_TOR -discover

List of known Bulwark Tor relays