arduino/Arduino · error · JSchException

Unable to find a way to connect

Error message

Unable to find a way to connect

What it means

SSHConfigFileSetup.setup is one link in a chain of SSH configuration strategies for connecting to a network board. If ~/.ssh/config does not exist and no next strategy in the chain can handle the connection, it throws this JSchException meaning no connection method succeeded.

Source

Thrown at arduino-core/src/cc/arduino/packages/ssh/SSHConfigFileSetup.java:57

  private final SSHClientSetupChainRing nextChainRing;

  public SSHConfigFileSetup(SSHClientSetupChainRing nextChainRing) {
    this.nextChainRing = nextChainRing;
  }

  @Override
  public Session setup(BoardPort port, JSch jSch) throws JSchException, IOException {
    String ipAddress = port.getAddress();

    File sshFolder = new File(System.getProperty("user.home"), ".ssh");
    File sshConfig = new File(sshFolder, "config");

    if (!sshFolder.exists() || !sshConfig.exists()) {
      if (nextChainRing != null) {
        return nextChainRing.setup(port, jSch);
      }
      throw new JSchException("Unable to find a way to connect");
    }

    OpenSSHConfig configRepository = OpenSSHConfig.parseFile(sshConfig.getAbsolutePath());

    jSch.setConfigRepository(new OpenSSHConfigWrapper(configRepository, ipAddress));

    return jSch.getSession(ipAddress);
  }

  public static class OpenSSHConfigWrapper implements ConfigRepository {

    private final OpenSSHConfig config;
    private final String ipAddress;

    public OpenSSHConfigWrapper(OpenSSHConfig config, String ipAddress) {
      this.config = config;
      this.ipAddress = ipAddress;
    }

View on GitHub (pinned to a0df6e0e83)

Solutions

1. Verify the board's IP address and that it is reachable (ping)
2. Create/populate ~/.ssh/config with a Host entry for the board, or let the IDE password prompt proceed
3. Check ~/.ssh directory permissions (700) and config permissions (600)
4. Reset the board and retry, since the board may have dropped off the network

Example fix

// before: no ~/.ssh/config
// after
Host myyun
  HostName 192.168.240.1
  User root

File cfg = new File(System.getProperty("user.home"), ".ssh/config");
if (!cfg.exists()) {
    // ensure an SSH config Host entry exists or expect password fallback prompt
}

try {
    connect(port);
} catch (JSchException e) {
    if (e.getMessage().equals("Unable to find a way to connect")) {
        // create ~/.ssh/config or verify board address, then retry
    }
}

When it happens

Trigger: Connecting to a network (Yún-style) board when ~/.ssh directory or ~/.ssh/config file is missing AND all previous/next chain strategies (default password/identity based) failed or were absent.

Common situations: Fresh machines with no SSH setup trying to reach a network board; wrong IP address so authentication strategies never apply; permissions issues preventing reading ~/.ssh/config.

Understand the failure class

Background: "Config file not found": what it means and how to fix it in docker-sync, Maven, Vagrant, Turborepo and other tools — this error's family across 60 libraries.

Related errors

• Unable to understand proxy settings
• Unable to connect to {0}
• Can't burn bootloader via SSH
• Board is not selected
• CRC doesn't match, file is corrupted. It may be a temporary

AI-assisted analysis of arduino/Arduino@a0df6e0e83 (2026-09-06). Data as JSON: /api/errors/c7f8f1434db9bfbb. Report an issue: GitHub.