# Certificate management in VPNs

Certificate management tasks in the SMC mostly involve VPN Gateways that represent engines.

VPN certificates can be generated by any internal or external certificate authorities that both gateways are configured to trust. There are several options for signing VPN Gateway certificates:

- The Management Server includes a dedicated Internal RSA CA for Gateways and optionally an Internal ECDSA CA for Gateways for signing VPN certificates. You use these certificate authorities through the SMC Client.
- One Internal CA for Gateways can be selected as the default CA. Certificate management can be automatic if the certificate is signed using the Management Server’s internal default CA.
- You can create certificate requests in the SMC Client, export them, sign them using an external CA, and then import the signed certificate back into the SMC.

RSA certificates can be created and renewed automatically using the default CA. Some manual steps are required in the following cases:

- You have both an Internal RSA CA for Gateways and an Internal ECDSA CA for Gateways. Only one Internal CA for Gateways can be selected as the default certificate authority. You must manually create and renew any certificates that are not signed by the default CA.
- You use DSA certificates.
- You want to use an external CA to sign certificates.

The Internal RSA CA for Gateways or Internal ECDSA CA for Gateways can also sign certificate requests created by external components. This feature is meant to support VPN client deployments. If you have used the Internal RSA CA for Gateways or Internal ECDSA CA for Gateways to sign certificate requests, you cannot cancel the issued certificates. Consider how widely you can use them for signing external certificate requests within your organization.