Table of contents¶
I don’t know where to start, help me !¶
There is a C-lightning plugin specifically for this purpose, it’s called
Assuming you have followed the installation steps, have
up and running, and
lightning-cli in your
$PATH you can start the plugin like so:
# Clone the plugins repository git clone https://github.com/lightningd/plugins # Make sure the helpme plugin is executable (git should have already handled this) chmod +x plugins/helpme/helpme.py # Install its dependencies (there is only one actually) pip3 install --user -r plugins/helpme/requirements.txt # Then just start it :) lightning-cli plugin start $PWD/plugins/helpme/helpme.py
The plugin registers a new command
helpme which will guide you through the main
components of C-lightning:
How to get the balance of each channel ?¶
You can use the
listfunds command and take a ratio of
amount_msat. Note that this doesn’t account for the channel reserve.
A better option is to use the
which nicely displays channel balances, along with other useful channel information.
My channel is in state
STATE, what does that mean ?¶
See the listpeers command manpage.
My payment is failing / all my payments are failing, why ?¶
There are many reasons for a payment failure. The most common one is a failure along the route from you to the payee. The best (and most common) solution to a route failure problem is to open more channels, which should increase the available routes to the recipient and lower the probability of a failure.
Hint: use the pay command which is will iterate through trying all possible routes,
instead of the low-level
sendpay command which only tries the passed in route.
How can I receive payments ?¶
In order to receive payments you need inbound liquidity. You get inbound liquidity when another node opens a channel to you or by successfully completing a payment out through a channel you opened.
If you need a lot of inbound liquidity, you can use a service that trustlessly swaps on-chain Bitcoin for Lightning channel capacity. There are a few online service providers that will create channels to you. A few of them charge fees for this service. Note that if you already have a channel open to them, you’ll need to close it before requesting another channel.
Are there any issues if my node changes its IP address? What happens to the channels if it does?¶
There is no risk to your channels if your IP address changes. However, be sure to change your announced address (or setup a TOR hidden service) in your config so that others can establish connections at your new address !
Can I have two hosts with the same public key and different IP addresses, both online and operating at the same time?¶
Can I use a single
bitcoind for multiple
bitcoind calls are handled by the bundled
lightningd does not use
bitcoind’s wallet. While on the topic,
lightningd does not require the
-txindex option on
If you use a single
bitcoind for multiple
lightningd’s, be sure to raise the
max RPC thread limit (
lightningd can use up to 4 threads, which is
Can I use C-lightning on mobile ?¶
lightningd on Android¶
Effort has been made to get
lightningd running on Android,
see issue #3484. Currently unusable.
How to “backup my wallet” ?¶
See BACKUP.md for a more comprehensive discussion of your options.
In summary: as a Bitcoin user, one may be familiar with a file or a seed (or some mnemonics) from which it can recover all its funds.
C-lightning has an internal bitcoin wallet, which you can use to make “on-chain”
transactions, (see withdraw.
These on-chain funds are backed up via the HD wallet seed, stored in byte-form in
lightningd also stores information for funds locked in Lightning Network channels, which are stored
in a database. This database is required for on-going channel updates as well as channel closure.
There is no single-seed backup for funds locked in channels.
While crucial for node operation, snapshot-style backups of the
lightningd database is discouraged,
as any loss of state may result in permanent loss of funds.
See the penalty mechanism
for more information on why any amount of state-loss results in fund loss.
Real-time database replication is the recommended approach to backing up node data.
Tools for replication are currently in active development, using the
Rescanning the block chain for lost utxos¶
There are 3 types of ‘rescans’ you can make:
bitcoindRPC call which rescans the blockchain starting at the given height. This does not have an effect on c-lightning as
lightningdtracks all block and wallet data independently.
lightningdconfiguration flag. This flag is read at node startup and tells lightningd at what depth from current blockheight to rebuild its internal state. (You can specify an exact block to start scanning from, instead of depth from current height, by using a negative number.)
lightningdRPC call. Only available if your node has been configured and built in DEVELOPER mode (i.e.
./configure --enable-developer) This will sync the state for known UTXOs in the
bitcoind. As it only operates on outputs already seen on chain by the
lightningdinternal wallet, this will not find missing wallet funds.
Database corruption / channel state lost¶
If you lose data (likely corrupted
lightningd.sqlite3) about a channel with
you can wait for your peer to unilateraly close the channel, then use
tools/hsmtool with the
guesstoremote command to attempt to recover your funds from the peer’s published unilateral close transaction.
option_static_remotekey was not enabled, you’re probably out of luck. The keys for your funds in your peer’s
unilateral close transaction are derived from information you lost. Fortunately, since version
are created with
option_static_remotekey by default if your peer supports it.
Which is to say that channels created after block 598000
(short channel id starting with > 598000) have a high chance of supporting
You can verify it using the
features field from the
listpeers command’s result.
Here is an example in Python checking if one of the
option_static_remotekey bits is set in the negotiated features corresponding to
>>> bool(0x02aaa2 & ((1 << 12) | (1 << 13))) True