If you are a LND node runner and want to commit to scaling the Lightning Network, then this guide is for you.
- Dunder LSP works only for LND nodes in combination with Blixt Wallet at the moment. Dunder LSP channels are private.
- You have to have some solid knowledge of how to use Terminal and Linux, as well as IP networks and proxy servers.
- I am far from being a developer, so this guide is built solely on my experience while setting up my own Dunder LSP Server https://lsp.btc-payserver.eu (no need to go there, dunder lsp servers do not have websites)
- I link to guides from experienced Bitcoiners and developers I used myself. But still -> do your own research.
Who else could put it in better words than DarthCoin ? Here is his detailled Dunder LSP Guide. There is also a short description on the Blixt Wallet homepage.
Log in to your LND node with Terminal and then head over to Hampus Sjöberg's Github Repository to get the code and start building the server. You may need to hop back and forth between his repository and my guide, here.
To check if your Dunder LSP server is up and running on your machine, type 127.0.0.1:8080 or 0.0.0.0:8080 in your browser (use the port you gave to your instance). If all is good, you will see hello, world and you are ready for the next step.
To be able to create an admin and have access to it, you first have to make your Dunder LSP server visible in clearnet. You will need a domain of your choice and a proxy server plus a valid SSL/TLS certificate for your domain.
Without that step you will not be able to create and access your Admin Dashboard. Start with adding your domain by cd dunder-lsp/config and nano default.json
like this:
"env": "development",
"serverHost": "127.0.0.1:8080",
"serverDomain": "https://<your Domain>",
- Use Caddy or Nginx, if you are familiar with them. This is the easiest way.
- Use Cloudflare (creating an account is easy, but setting the tunnel up in terminal is a bit tricky). For this setup you also need to have
cloudflaredinstalled on your machine.
Proceed in Terminal with Hampus Sjöberg's guide to create a temporary HTTP server. Scan the created QR code with your wallet of joice, preferable Blixt. Keep in mind that your Dunder LSP server must be stopped for that process. If you use another wallet, that other wallet will be irreversable connected to your Dunder LSP server. The only chance you have is to create another admin with another wallet later in your Admin Dashboard.
If you have successfully created your /admin you will be able to access your Dashboard in your browser with <yourDomain>/admin . A login QR code will be crated which you have to scan with the same wallet you used to create the admin (Blixt). I recommend Blixt as it makes sense to be in the same workflow as your Dunder LSP server. Be aware that Brave browser has issues (the generated QR code was unresponsive and it took me a while to figure that out). I had to use Safari on Mac. Chrome works fine, too.
This is what you will see after you typed <yourDomain>/admin into your browser:
... and after login - your Admin Dashboard (in this case from my Dunder LSP server). Nice and slick.
At the moment, there is no other way to set your fees than in Terminal. You have to cd dunder-lsp/config and then nano default.json
Here is how I have mine set up for now:
"minimumPaymentMultiplier": 5,
"maximumPaymentSat": 410000,
"fee": {
"maxSat": 40000,
"maxSatPerVByte": 200,
"subsidyFactor": 1
Of course, you can set the channel size and fees as you see fit.
This parameter sets a rule for the minimum allowed payment amount in a transaction. The minimum payment amount is calculated by multiplying this multiplier with some base value. For example, if the base value is 10,000 satoshis, then the minimum payment amount would be 5 times that, which is 50,000 satoshis.
This parameter establishes the maximum amount of satoshis that can be sent in a single payment or transaction (in this case 410,000 Stats). If a user attempts to send more than this specified amount, the transaction may be rejected or adjusted to comply with this limit. If a user wants to have a 410,000 Sats channel opened, he needs to send the maximum amount of 80,000 Sats to do so. This basically means that channels are restricted to a maximum size of 410,000 Sats each from the Dunder LSP server side.
This sets the maximum allowable transaction fee in satoshis. Users creating transactions are restricted from setting a fee higher than this value.
This parameter sets the maximum fee rate per virtual byte in satoshis. Transaction fees are calculated based on the size (in virtual bytes) of the transaction. This parameter imposes an upper limit on the fee rate.
The subsidy factor is related to how transaction fees are subsidized. The subsidy factor of 1 sets that the on-chain fees are paid by the channel opening peer (user) and not the Dunder LSP node.
(can this be called so ?)
If mempool fees exceed 200/vB (as set in default.json ), Dunder LSP server will automatically shut down to protect the user from paying too high on-chain fees. It should automatically start up if mempool fees are back on the set level. ANYTHING ELSE TO ADD HERE ?
There are currently two ways a user can onboard to Blixt wallet.
-
The user simply pays an on-chain amount of his choice (min. 22.000 Sats) and automatically gets a Lightning Network channel opened with outbound liquidity for the same amount (minus on-chain fees). This method currently works only through the Blixt node by default and has nothing to do with any Dunder server.
-
A user, who already has LN liquidity can open a channel with your Dunder LSP server by selecting your server in the settings (default is: https//dunder.blixtwallet.com). He then creates an invoice with his Blixt wallet. No matter the amount a user creates an invoice for, your Dunder LSP server opens a channel with the max. amount you chose in the
default.json(in my case 400,000 Sats) and "borrows" the user the additional amount. Then your Dunder LSP server usespush-amt(push amount) and pushes the initial channel opening amount (minus the on-chain fees for channel opening) to the users side. Now the user has a private channel to you with outbound and inbound liquidity. These channels are not visible to other nodes in the Lightning network. You are routing these "Dunder" payments through your public channels. That is why you have to be well connected with good routing nodes.
It is absolutely necessary to keep your Dunder LSP server up and running at any time if you want to provide a reliable service for other Lightning Network users. Create a systemd dunder.service file to do so:
cd /etc/systemd/system and then nano dunder.service Here is how i set up mine. You can copy paste it and fill in your personal data.
Description=Dunder LSP
[Service]
WorkingDirectory=/<your path to>/<your path to>/dunder-lsp/
ExecStart=npm start
Type=simple
KillMode=control-group
TimeoutSec=180
Restart=always
RestartSec=60
User=<your username>
[Install]
WantedBy=multi-user.target
Make sure you sudo systemctl reload <service-name> or sudo systemctl daemon-reload after saving the file.
DarthCoin made a nice graphic how your node is now connected to the Lightning Netork. You can also see how Blixt users will connect to you if they choose your server.
It is absolutely important to keep in mind that you are providing liquidity for others out of your own pocket. You must have enough liquidity on-chain on your LND node.
It is a good idea to install Blixt Wallet on your smartphone to do some testing with your own Dunder LSP server. Go to "Settings" and "Enable Dunder LSP". Then "Set Dunder LSP" to your servers URL and test if you are up and running by "Diagnose Dunder problems" further down in the debug section. If you have not enough funds on your node you will see an error. Same if mempool fees are too high and server automatically shut down.
Feel free to comment here or get in contact on Telegram @SatoshiSamourai or via email: [email protected]