🗝️Troubleshoot SSH Connection

Introduction

This guide is designed to help you troubleshoot and restore SSH access to your Validator node when it was previously working but is now unreachable.

♻️How to SSH into VPS

Common Steps

✅ Verify the username for the VPS you're connecting to

• e.g.) nodeadmin

✅ Check your SSH key pair file names

• Private key must match the server's authorized key.

✅ Confirm correct permissions

• private key should be read-only: chmod 400

✅ Ensure the public key exists on the server in the correct location

✅ Confirm the private key file exists locally

• Is it correctly referenced by your SSH command.

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🏠 Local IP address

Many ISPs assign dynamic IP addresses to customer routers.

A change in your IP may cause your cloud provider’s firewall to block your SSH attempts.

🩹Symptoms:

Your SSH terminal or remote connection application sits idle and eventually shows Connection timed out messages.
Terminal or remote terminal application will how a blank screen only
No password or key prompts appear
Not entering the SSH connection string and attempting to run commands locally instead of through your SSH tunnel.

💡 Example:

ssh -i ~/.ssh/my_identity_file nodeadmin@13.13.13.13
ssh: connect to host 13.13.13.13 port 22: Operation timed out

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🔧 How to Fix It

1

Determine your new IP address

Open your web browser and navigate to:

www.whatismyip.com

2

Record New IP Address

Copy your current public IPv4 address

3

Cloud Provider Console

Go to your cloud provider's web console.

4

Update Firewall Rules

Update your firewall or security group rules to allow SSH access from your new IP

• AWS: Update the Security Group

• DigitalOcean: Update Firewall settings

• Hetzner: Follow DigitalOcean-style firewall update workflow

Refer to the Cloud Provider Specific Guides.

Try connecting again after updating the rules.

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🔐 SSH Key Issues

📍 Local Key Issues

Ensure the private key file:

• Still exists in the expected location

• Has not been renamed or moved

• Is intact and not corrupted

• Has the proper permissions

📌 Tip:

If in doubt, restore your key from a known-good backup.

Important: Once resolved, create a backup of your SSH keys if you haven’t already.

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📡 Remote Key Issues (Accessing via Console)

If you can still access your VPS through your cloud provider's web console:

1

Log into the Web Terminal

2

Navigate to the .ssh Directory

cd ~/.ssh
ls -l

3

Verify Public Key

Check for the authorized public key file

authorized_keys or .pub file.

If the key is missing or incorrect:

Check alternate directories:

ls -l /root/.ssh/
ls -l /home/ubuntu/.ssh/
ls -l /home/admin/.ssh/

4

Identify _backup

If you find your key with a _backup attached to the name of the file, issue the following command and check again:

Enable root SSH temporarily:

sudo nodectl enable_root_ssh

5

Copy SSH Key Back Over

Copy the key into your nodeadmin’s .ssh directory :

sudo cp /root/.ssh/mypublickey.pub /home/nodeadmin/.ssh/mypublickey.pub

Change ownership

sudo chown nodeadmin:nodeadmin /home/nodeadmin/.ssh/mypublickey.pub

6

Disable Root Access Again

sudo nodectl disable_root_ssh

Re-Attempt to create an SSH connection to your node.

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📡 Cloud Provider Outage

• Visit your cloud provider’s main dashboard

• Look for service alerts

• If the console is also unreachable, check external outage reports

  • Google

  • Twitter

  • Downdetector

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🖥️ VPS-Specific Issue

• From the cloud console, check the status of your VPS instance

• Ensure it’s running and not reporting hardware or OS-level errors

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🌍 Local Internet Outage

• If you cannot connect to any external site or service, confirm your own network is online

• Restart your router/modem if necessary and try again later