Using Tor
To use any Tor features with Core Lightning you must have Tor installed and running.
Note that we only support Tor v3: you can check your installed Tor version with tor --version
or sudo tor --version
If Tor is not installed you can install it on Debian based Linux systems (Ubuntu, Debian, etc) with the following command:
sudo apt install tor
then /etc/init.d/tor start
or sudo systemctl enable --now tor
depending on your system configuration.
Most default setting should be sufficient.
To keep a safe configuration for minimal harassment (See Tor FAQ) just check that this line is present in the Tor config file /etc/tor/torrc
:
ExitPolicy reject *:* # no exits allowed
This does not affect Core Lightning connect, listen, etc. It will only prevent your node from becoming a Tor exit node. Only enable this if you are sure about the implications.
If you don't want to create .onion addresses this should be enough.
There are several ways by which a Core Lightning node can accept or make connections over Tor. The node can be reached over Tor by connecting to its .onion address.
To provide the node with a .onion address you can:
-
create a non-persistent address with an auto service or
-
create a persistent address with a hidden service.
Quick Start On Linux
It is easy to create a single persistent Tor address and not announce a public IP. This is ideal for most setups where you have an ISP-provided router connecting your Internet to your local network and computer, as it does not require a stable public IP from your ISP (which might not give one to you for free), nor port forwarding (which can be hard to set up for random cheap router models). Tor provides NAT-traversal for free, so even if you or your ISP has a complex
network between you and the Internet, as long as you can use Tor you can be connected to.
Core Lightning also support IPv4/6 address discovery behind NAT routers.
For this to work you need to forward the default TCP port 9735 to your node. In this case you don't need TOR to punch through your firewall. IP discovery is only active if no other addresses are announced. This usually has the benefit of quicker and more stable connections but does not
offer additional privacy.
On most Linux distributions, making a standard installation of tor
will automatically set it up to have a SOCKS5 proxy at port 9050. As well, you have to set up the Tor Control Port. On most Linux distributions there will be commented-out settings below in the
/etc/tor/torrc
:
ControlPort 9051
CookieAuthentication 1
CookieAuthFile /var/lib/tor/control_auth_cookie
CookieAuthFileGroupReadable 1
Uncomment those in, then restart tor
(usually systemctl restart tor
or
sudo systemctl restart tor
on most SystemD-based systems, including recent Debian and Ubuntu, or just restart the entire computer if you cannot figure it out).
On some systems (such as Arch Linux), you may also need to add the following setting:
DataDirectoryGroupReadable 1
You also need to make your user a member of the Tor group.
"Your user" here is whatever user will run lightningd
. On Debian-derived systems, the Tor group will most likely be debian-tor
. You can try listing all groups with the below command, and check for a debian-tor
or tor
groupname.
getent group | cut -d: -f1 | sort
Alternately, you could check the group of the cookie file directly.
Usually, on most Linux systems, that would be /run/tor/control.authcookie
:
stat -c '%G' /run/tor/control.authcookie
Once you have determined the ${TORGROUP}
and selected the
${LIGHTNINGUSER}
that will run lightningd
, run this as root:
usermod -a -G ${TORGROUP} ${LIGHTNINGUSER}
Then restart the computer (logging out and logging in again should also work).
Confirm that ${LIGHTNINGUSER}
is in ${TORGROUP}
by running the groups
command as ${LIGHTNINGUSER}
and checking ${TORGROUP}
is listed.
If the /run/tor/control.authcookie
exists in your system, then log in as the user that will run lightningd
and check this command:
cat /run/tor/control.authcookie > /dev/null
If the above prints nothing and returns, then Core Lightning "should" work with your Tor.
If it prints an error, some configuration problem will likely prevent Core Lightning from working with your Tor.
Then make sure these are in your ${LIGHTNING_DIR}/config
or other Core Lightning configuration (or prepend --
to each of them and add them to your lightningd
invocation
command line):
proxy=127.0.0.1:9050
bind-addr=127.0.0.1:9735
addr=statictor:127.0.0.1:9051
always-use-proxy=true
proxy
informs Core Lightning that you have a SOCKS5 proxy at port 9050.
Core Lightning will assume that this is a Tor proxy, port 9050 is the default in most Linux distributions; you can double-check/etc/tor/torrc
for aSocksPort
entry to confirm the port number.bind-addr
informs Core Lightning to bind itself to port 9735.
This is needed for the subsequentstatictor
to work.
9735 is the normal Lightning Network port, so this setting may already be present.
If you add a secondbind-addr=...
you may get errors, so choose this new one or keep the old one, but don't keep both.
This has to appear before anystatictor:
setting.addr=statictor:
informs Core Lightning that you want to create a persistent hidden service that is based on your node private key.
This informs Core Lightning as well that the Tor Control Port is 9051. You can also usebind-addr=statictor:
instead to not announce the persistent hidden service, but if anyone wants to make a channel with you, you either have to connect to them, or you have to reveal your address to them explicitly (i.e. autopilots and the like will likely never connect to you).always-use-proxy
informs Core Lightning to always use Tor even when connecting to nodes with public IPs. You can set this tofalse
or remove it, if you are not privacy-conscious and find Tor is too slow for you.
Tor Browser and Orbot
It is possible to not install Tor on your computer, and rely on just Tor Browser.
Tor Browser will run a built-in Tor instance, but with the proxy at port 9150 and the control port at 9151 (the normal Tor has, by default, the proxy at port 9050 and the control
port at 9051). The mobile Orbot uses the same defaults as Tor Browser (9150 and 9151).
You can then use these settings for Core Lightning:
proxy=127.0.0.1:9150
bind-addr=127.0.0.1:9735
addr=statictor:127.0.0.1:9151
always-use-proxy=true
You will have to run Core Lightning after launching Tor Browser or Orbot, and keep Tor Browser or Orbot open as long as Core Lightning is running, but this is a setup which allows others to connect and fund channels to you, anywhere (no port forwarding! works wherever Tor works!), and you do not have to do anything more complicated than download and install Tor Browser.
This may be useful for operating system distributions that do not have Tor in their repositories, assuming we can ever get Core Lightning running on those.
Detailed Discussion
Three Ways to Create .onion Addresses for Core Lightning
- You can configure Tor to create an onion address for you, and tell Core Lightning to use that address
- You can have Core Lightning tell Tor to create a new onion address every time
- You can configure Core Lightning to tell Tor to create the same onion address every time it starts up
Tor-Created .onion Address
Having Tor create an onion address lets you run other services (e.g. a web server) at that same address, and you just tell that address to Core Lightning and it doesn't have to talk to the Tor server at all.
Put the following in your /etc/tor/torrc
file:
HiddenServiceDir /var/lib/tor/lightningd-service_v3/
HiddenServiceVersion 3
HiddenServicePort 1234 127.0.0.1:9735
The hidden lightning service will be reachable at port 1234 (global port) of the .onion address, which will be created at the restart of the Tor service. Both types of addresses can coexist on the same node.
Save the file and restart the Tor service. In linux:
/etc/init.d/tor restart
or sudo systemctl restart tor
depending on the configuration of your system.
You will find the newly created address (myaddress.onion) with:
sudo cat /var/lib/tor/lightningd-service_v3/hostname
Now you need to tell Core Lightning to advertize that onion hostname and port, by placing announce-addr=myaddress.onion
in your lightning config.
Letting Core Lightning Control Tor
To have Core Lightning control your Tor addresses, you have to tell Tor to accept control commands from Core Lightning, either by using a cookie, or a password.
Service authenticated by cookie
This tells Tor to create a cookie file each time: lightningd will have to be in the same group as tor (e.g. debian-tor): you can look at /run/tor/control.authcookie
to check the group name.
Add the following lines in the /etc/tor/torrc
file:
ControlPort 9051
CookieAuthentication 1
CookieAuthFileGroupReadable 1
Save the file and restart the Tor service.
Service authenticated by password
This tells Tor to allow password access: you also need to tell lightningd what the password is.
Create a hash of your password with
tor --hash-password yourpassword
This returns a line like
16:533E3963988E038560A8C4EE6BBEE8DB106B38F9C8A7F81FE38D2A3B1F
Put these lines in the /etc/tor/torrc
file:
ControlPort 9051
HashedControlPassword 16:533E3963988E038560A8C4EE6BBEE8DB106B38F9C8A7F81FE38D2A3B1F
Save the file and restart the Tor service.
Put tor-service-password=yourpassword
(not the hash) in your lightning configuration file.
Core Lightning Creating Persistent Hidden Addresses
This is usually better than transient addresses, as nodes won't have to wait for gossip propagation to find out your new address each time you restart.
Once you've configured access to Tor as described above, you need to add two lines in your lightningd config file:
- A local address which lightningd can tell Tor to connect to when connections come in, e.g.
bind-addr=127.0.0.1:9735
. - After that, a
addr=statictor:127.0.0.1:9051
to tell Core Lightning to set up and announce a Tor onion address (and tell Tor to send connections to our real address, above).
You can use bind-addr
if you want to set up the onion address and not announce it to the world for some reason.
You may add more addr
lines if you want to advertise other addresses.
There is an older method, called "autotor" instead of "statictor" which creates a different Tor address on each restart, which is usually not very helpful; you need to use lightning-cli getinfo` to see what address it is currently using, and other peers need to wait for fresh gossip messages if you announce it, before they can connect.
What do we support
Case # | IP Number | Hidden service | Incoming / Outgoing Tor |
---|---|---|---|
1 | Public | NO | Outgoing |
2 | Public | FIXED BY TOR | Incoming [1] |
3 | Public | FIXED BY CORE LIGHTNING | Incoming [1] |
4 | Not Announced | FIXED BY TOR | Incoming [1] |
5 | Not Announced | FIXED BY CORE LIGHTNING | Incoming [1] |
In all the "Incoming" use case, the node can also make "Outgoing" Tor
connections (connect to a .onion address) by adding theproxy=127.0.0.1:9050
option.
Case #1: Public IP address and no Tor address, but can connect to Tor addresses
Without a .onion address, the node won't be reachable through Tor by other nodes but it will always be able to connect
to a Tor enabled node (outbound connections), passing the connect
request through the Tor service socks5 proxy. When the Tor service starts it creates a socks5 proxy which is by default at the address 127.0.0.1:9050.
If the node is started with the option proxy=127.0.0.1:9050
the node will be always able to connect to nodes with .onion address through the socks5 proxy.
You can always add this option, also in the other use cases, to add outgoing
Tor capabilities.
If you want to connect
to nodes ONLY via the Tor proxy, you have to add the always-use-proxy=true
option (though if you only advertize Tor addresses, we also assume you want to always use the proxy).
You can announce your public IP address through the usual method: if your node is in an internal network:
bind-addr=internalIPAddress:port
announce-addr=externalIpAddress
or if it has a public IP address:
addr=externalIpAddress
If you are unsure which of the two is suitable for you, find your internal and external address and see if they match.
In linux:
Discover your external IP address with: curl ipinfo.io/ip
and your internal IP Address with: ip route get 1 | awk '{print $NF;exit}'
.
If they match you can use the --addr
command line option.
Case #2: Public IP address, and a fixed Tor address in torrc
Other nodes can connect to you entirely over Tor, and the Tor address doesn't change every time you restart.
You simply tell Core Lightning to advertize both addresses (you can use sudo cat /var/lib/tor/lightningd-service_v3/hostname
to get your Tor-assigned onion address).
If you have an internal IP address:
bind-addr=yourInternalIPAddress:port
announce-addr=yourexternalIPAddress:port
announce-addr=your.onionAddress:port
Or an external address:
addr=yourIPAddress:port
announce-addr=your.onionAddress:port
Case #3: Public IP address, and a fixed Tor address set by Core Lightning
Other nodes can connect to you entirely over Tor, and the Tor address doesn't change every time you restart.
See "Letting Core Lightning Control Tor" for how to get Core Lightning talking to Tor.
If you have an internal IP address:
bind-addr=yourInternalIPAddress:port
announce-addr=yourexternalIPAddress:port
addr=statictor:127.0.0.1:9051
Or an external address:
addr=yourIPAddress:port
addr=statictor:127.0.0.1:9051
Case #4: Unannounced IP address, and a fixed Tor address in torrc
Other nodes can only connect to you over Tor.
You simply tell Core Lightning to advertize the Tor address (you can use sudo cat /var/lib/tor/lightningd-service_v3/hostname
to get your Tor-assigned onion address).
announce-addr=your.onionAddress:port
proxy=127.0.0.1:9050
always-use-proxy=true
Case #4: Unannounced IP address, and a fixed Tor address set by Core Lightning
Other nodes can only connect to you over Tor.
See "Letting Core Lightning Control Tor" for how to get Core Lightning
talking to Tor.
addr=statictor:127.0.0.1:9051
proxy=127.0.0.1:9050
always-use-proxy=true
References
- Configuring your node section (or
lightningd-config
manual page) covers the various address cases in detail. - The Tor project
- Tor FAQ
- Tor Hidden Service
- .onion addresses version 3
Updated 11 months ago