Your certificates are useless if no one can trust them.

In an air-gapped deployment, trust is built differently. No public Certificate Authority. No internet validation. No automated renewal. Every byte of TLS configuration must be handled inside the sealed environment — correctly, the first time.

Air-gapped TLS starts with a clear chain of trust. You control the root CA. You generate intermediate CAs if needed. You issue and sign every certificate locally. Nothing leaves the network. This means there’s no fallback if you mess up the subject names, SANs, validity, or key sizes. There’s no quick fix with Let’s Encrypt. Every decision has to be intentional.

To configure TLS in an air-gapped environment, choose a strong key algorithm (2048-bit RSA or better, or elliptic curve with P-256). Set reasonable validity periods — long enough to reduce maintenance risk, short enough to keep the attack window small. Include all required SANs for every service endpoint, even internal ones. If your nodes need mutual TLS, build and distribute the client certs with the same care as the server certs.

Test everything before rollout. In an air-gapped setup, deployment mistakes can mean days of outage while you regenerate and redistribute keys. Use offline OpenSSL or CFSSL tooling to inspect, verify, and validate your chain. Keep a secure vault of your CA keys, with both physical and procedural controls. Document every command, every parameter, every passphrase.

When deploying, configure your services to reject weak ciphers and enforce TLS 1.2+ (TLS 1.3 wherever supported). Pin certificates where possible. Disable renegotiation. Monitor logs for handshake errors — in an air-gapped system, failed TLS is often the first symptom of deeper breakage.

Air-gapped deployment TLS configuration is all about discipline: no shortcuts, no unchecked trust, no hidden dependencies. It’s the foundation for keeping secrets secure when the rest of the world is shut out.

If you want to see a secure, live environment in minutes — with TLS done right even in private or isolated networks — check out hoop.dev and watch it work without compromise.