diff --git a/doc/Tor.txt b/doc/Tor.txt new file mode 100644 index 000000000..f44b016f2 --- /dev/null +++ b/doc/Tor.txt @@ -0,0 +1,96 @@ +TOR SUPPORT IN BITCOIN +====================== + +It is possible to run Bitcoin as a Tor hidden service, and connect to such services. + +The following assumes 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 +https://www.torproject.org/docs/faq.html.en#TBBSocksPort for how to properly +configure Tor. + + +1. Run bitcoin behind a Tor proxy +--------------------------------- + +The first step is running Bitcoin behind a Tor proxy. This will already make all +outgoing connections be anonimized, but more is possible. + +-socks=5 SOCKS5 supports connecting-to-hostname, which can be used instead + of doing a (leaking) local DNS lookup. SOCKS5 is the default, + but SOCKS4 does not support this. (SOCKS4a does, but isn't + implemented). + +-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. + +-tor=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 -notor + to explicitly disable access to hidden service. + +-dnsseed DNS seeds are not resolved directly when a SOCKS5 proxy server is + set. Rather, a short-lived proxy connection to the dns seed + hostname is attempted, and peer addresses are requested. + +-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 behing 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. + +In a typical situation, this suffices to run behind a Tor proxy: + + ./bitcoin -proxy=127.0.0.1:9050 + + +2. Run a bitcoin 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): + + HiddenServiceDir /var/lib/tor/bitcoin-service/ + HiddenServicePort 8333 127.0.0.1:8333 + +The directory can be different of course, but (both) 8333's should be equal to your +bitcoind's P2P listen port (8333 by default). + +-externalip=X You can tell bitcoin about its publically 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/bitcoin-service/hostname. Onion addresses are given + preference for your node to advertize itself with, for connections + coming from unroutable addresses (such as 127.0.0.1, 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: + + ./bitcoind -proxy=127.0.0.1:9050 -externalip=57qr3yd1nyntf5k.onion -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: + + ./bitcoind ... -discover + +and open port 8333 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: + + ./bitcoin -tor=127.0.0.1:9050 -externalip=57qr3yd1nyntf5k.onion -discover +