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.

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

• Can't burn bootloader via SSH
• Unable to connect to
• Unable to understand proxy settings
• Board is not selected
• Burning bootloader is not supported via network!

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

Appendix: 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;
    }

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