*** Warning: Do not assume Tor support does the correct thing in Zcash; better Tor support is a future feature goal. ** *
TOR SUPPORT IN ZCASH
====================
It is possible to run Zcash 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 ](https://www.torproject.org/docs/faq.html.en#TBBSocksPort ) for how to properly
configure Tor.
1. Run Zcash behind a Tor proxy
-------------------------------
The first step is running Zcash 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.
In a typical situation, this suffices to run behind a Tor proxy:
./zcashd -proxy=127.0.0.1:9050
2. Run a Zcash 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/zcash-service/
HiddenServicePort 8233 127.0.0.1:8233
HiddenServicePort 18233 127.0.0.1:18233
The directory can be different of course, but (both) port numbers should be equal to
your zcashd's P2P listen port (8233 by default).
-externalip=X You can tell Zcash 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/zcash-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:
./zcashd -proxy=127.0.0.1:9050 -externalip=abc123.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:
./zcashd ... -discover
and open port 8233 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:
./zcashd -onion=127.0.0.1:9050 -externalip=abc123.onion -discover
3. Connect to a Zcash hidden server
-----------------------------------
To test your set-up, you might want to try connecting via Tor to just a
a single Zcash hidden server.
Edit zcash.conf and comment out any nodes you might normally connect to.
#addnode =alphatestnet.z.cash
Launch zcashd as follows:
zcashd -onion=127.0.0.1:9050 -addnode=abc123.onion
Now use zcash-cli to verify there is only a single peer connection.
zcash-cli getpeerinfo
[
{
"id" : 1,
"addr" : "abc123.onion:18233",
...
"version" : 70002,
"subver" : "/Satoshi:0.11.2/",
...
}
]
