Networking

Dedicated Public IP

Every Spheron GPU instance receives a dedicated public IP address when deployed. There is no shared IP, NAT, or port forwarding. Each instance has its own routable IP for the lifetime of the deployment.

When a deployment reaches running status, the IP address and SSH connection command are shown in the instance details panel in the dashboard.

SSH Access

# Use the SSH command from the instance details panel in the dashboard
ssh ubuntu@198.51.100.42
 
# Or with an explicit key
ssh -i ~/.ssh/id_ed25519 ubuntu@198.51.100.42

See SSH Connection for key setup and troubleshooting.

Port Access

All ports on your instance are open by default via its dedicated public IP. You can reach any service directly without any firewall configuration:

curl http://198.51.100.42:8000/v1/completions

Security

Because all ports are open by default, do not expose inference servers, Jupyter notebooks, or other unauthenticated services publicly without adding authentication.

Use SSH tunneling for development (see below). If you must expose a service publicly, add token-based authentication before doing so.

To restrict access, you can close specific ports using ufw in your startup script or after connecting:

# Allow only SSH and close everything else
ufw default deny incoming
ufw allow 22/tcp
ufw enable

SSH Tunneling

SSH tunneling forwards remote ports to your local machine without opening firewall rules or exposing services publicly.

Forward a remote port to your local machine:

# Forward port 8888 (Jupyter) to localhost
ssh -L 8888:localhost:8888 ubuntu@<ipAddress>
 
# Forward multiple ports at once
ssh -L 8888:localhost:8888 -L 8000:localhost:8000 ubuntu@<ipAddress>

Then open http://localhost:8888 in your browser.

VS Code Port Forwarding

If you use VS Code Remote SSH, the Ports tab in VS Code lets you forward ports visually without typing SSH tunnel commands. This is the easiest way to forward Jupyter (8888) and TensorBoard (6006).

Additional Resources

SSH Connection: Key setup and connection troubleshooting
VS Code Remote: Remote development and port forwarding panel
Security Best Practices: Secure your instances and data
Startup Script: Cloud-init examples including firewall configuration
API Reference: Retrieve IP address and SSH connection details programmatically