*** 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 port 9150. 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=zctestseie6wxgio.onion -listen
(obviously, replace the Onion address with your own). It should be noted that you still
listen on all devices and another node could establish a clearnet connection, when knowing
your address. To mitigate this, additionally bind the address of your Tor proxy:
./bitcoind ... -bind=127.0.0.1
If you don't care too much about hiding your node, and want to be reachable on IPv4
as well, use `discover` instead:
./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=zctestseie6wxgio.onion -discover
3. Automatically listen on Tor
--------------------------------
Starting with Tor version 0.2.7.1 it is possible, through Tor's control socket
API, to create and destroy 'ephemeral' hidden services programmatically.
Zcash has been updated to make use of this.
This means that if Tor is running (and proper authorization is available),
Zcash automatically creates a hidden service to listen on, without
manual configuration. Zcash will also use Tor automatically to connect
to other .onion nodes if the control socket can be successfully opened. This
will positively affect the number of available .onion nodes and their usage.
This new feature is enabled by default if Zcash is listening, and
a connection to Tor can be made. It can be configured with the `-listenonion` ,
`-torcontrol` and `-torpassword` settings. To show verbose debugging
information, pass `-debug=tor` .
4. Connect to a Zcash hidden server
-----------------------------------
To test your set-up, you might want to try connecting via Tor on a different computer to just a
a single Zcash hidden server. Launch zcashd as follows:
./zcashd -onion=127.0.0.1:9050 -connect=zctestseie6wxgio.onion
Now use zcash-cli to verify there is only a single peer connection.
zcash-cli getpeerinfo
[
{
"id" : 1,
"addr" : "zctestseie6wxgio.onion:18233",
...
"version" : 170002,
"subver" : "/MagicBean:1.0.0/",
...
}
]
To connect to multiple Tor nodes, use:
./zcashd -onion=127.0.0.1:9050 -addnode=zctestseie6wxgio.onion -dnsseed=0 -onlynet=onion
