This section explains how to solve some known or frequently encountered issues.

If what you need is not in this section, please contact us without hesitation through the RSK Community on Slack. We will be happy to help you!



Discovery can’t be started

On Windows, if you start the node and it doesn’t do anything, there is a high chance you have a problem with the UDP port of the node.

The UDP port is configured in the node’s configuration file, specifically with the value peer.port. By default this port is configured to 5050.

To check if that port is already taken by other application you can follow these steps:

  • Open a cmd console and run netstat -ano -p UDP | findstr :5050 (or replace 5050 with the port of your preference).
  • You will get a result with the process ID (if any) already using that port for UDP.
  • With the process ID (the value at the far right), run this command tasklist /FI "PID eq processId-you-got".

This will let you know which application/service is using this port.

Please make sure the port of your preference is not taken by other application. If so, you need to change the node configuration as explained here, by overwriting the peer port option.

Note: we are considering the possibility of changing this port (5050) in future releases to avoid this problem.

I don’t see the logs

You can configure your own log level, following these instructions.

Plugin with id witness not found

If you have this error it’s possible that you have missed to run rskj’s dependencies. So please, follow the instructions depending on your operation system:

Truffle doesn’t seem to work connected to RSK

If you can not get truffle migrate complete, you will see something like:

Writing artifacts to ./build/contracts
Using network 'development'.
Running migration: 1_initial_migration.js
  Deploying Migrations...
  ... 0xc82d661d579e40d22c732b2162734f97aeb13fa095946927cbb8cd896b26a7a3

Be sure you are using the right configuration in the truffle.js and truffle-config.js files.

Remember that you need: node host, node port, network_id and in some cases the from (by default Truffle uses the first account in the node). This last one should be an account with positive balance (because it’s the one Truffle uses to deploy contract and run transactions) and it should be present between the node’s accounts (you can know that by executing the web3.eth.accounts command).

So, your config file should be like this:

module.exports = {
    networks : {
        rsk: {
            from : "0xcd2a3d9f938e13cd947ec05abc7fe734df8dd826",
            host : "localhost",
            port : 4444,
            network_id : "*" // Match any network id

Can’t get public IP

If you get the error: Can't get public IP when you’re trying to run your rskj node, the reason is that rskj uses Amazon Check IP service to set the public.ip parameter.

To solve it, you need to change the public.ip key in config file with your IP address (if you don’t know your IP, simply search for it).

This page will show you how to change a node’s configuration file.

Rewind Blocks

This tool should be used in a scenario where an RSK node processes blocks that are corrupted or invalid, for example after a hard fork. It allows one to remove such blocks and start from a previously known state. It does so by removing the blocks with block number higher than the block number parameter command line argument.

Note: The node must be turned off before the rewind, and restarted after.


java -cp rsk-core-<VERSION>.jar 1000000

The above command removes the blocks with number 1000001 or higher.