Network Access

Sandboxes use Kubernetes NetworkPolicies for network isolation.

Default access

• Internet - can reach external services (needed for LLM APIs)
• Control-plane - can talk to Netclode control-plane
• DNS - can resolve domains
• No private networks - blocked from 10.0.0.0/8, 172.16.0.0/12, 192.168.0.0/16
• No Tailnet by default - blocked from 100.64.0.0/10

Tailnet access

Enable with --tailnet to let the sandbox reach your Tailscale network:

netclode sessions create --repo owner/repo --tailnet

Useful for accessing internal APIs, databases, or package registries on your tailnet.

Flags	Internet	Tailnet
(default)	Allowed	Blocked
--tailnet	Allowed	Allowed

How it works

Each sandbox gets NetworkPolicies:

1. Base policy - DNS + control-plane access
2. Internet access - allows 0.0.0.0/0 except private ranges
3. Tailnet access (if --tailnet) - allows 100.64.0.0/10

# Internet access policy (always created)
apiVersion: networking.k8s.io/v1
kind: NetworkPolicy
metadata:
  name: sess-<id>-internet-access
spec:
  egress:
    - to:
        - ipBlock:
            cidr: 0.0.0.0/0
            except:
              - 10.0.0.0/8
              - 172.16.0.0/12
              - 192.168.0.0/16
              - 100.64.0.0/10

# Tailnet access policy (created with --tailnet)
apiVersion: networking.k8s.io/v1
kind: NetworkPolicy
metadata:
  name: sess-<id>-tailnet-access
spec:
  egress:
    - to:
        - ipBlock:
            cidr: 100.64.0.0/10

NetworkPolicies are additive, so the tailnet policy adds to the default internet access.

Troubleshooting

# List policies for a session
kubectl --context netclode -n netclode get networkpolicies | grep <session-id>

Tailnet not accessible with --tailnet - verify the sess-<id>-tailnet-access NetworkPolicy exists.

DNS not working - check CoreDNS pods are running in kube-system.