Crypto PKI Trustpoint & DNAC CA: Securing Cisco Networks with Certificate Authority

What is Crypto PKI Trustpoint and DNAC CA?

Crypto PKI Trustpoint and DNAC CA represent critical components in Cisco’s security ecosystem. PKI (Public Key Infrastructure) establishes trusted digital identities through cryptographic certificates, while a Trustpoint in Cisco IOS/XE devices defines certificate authority parameters. DNAC (DNA Center) CA is Cisco’s integrated certificate authority within its network controller, automating certificate lifecycle management for devices like switches and routers. Together, they enable encrypted communications, device authentication, and zero-trust architectures in enterprise networks.

How PKI Trustpoints Work in Cisco Environments

Trustpoints act as configuration profiles that tell Cisco devices how to interact with CAs. Key functions include:

• Certificate Enrollment: Devices use trustpoints to request certificates from CAs via protocols like SCEP.
• Trust Validation: Defines which CA root certificates are trusted for verifying peer identities.
• Revocation Checking: Configures CRL (Certificate Revocation List) or OCSP validation paths.
• Key Management: Governs RSA key generation and storage for certificate pairs.

Example CLI command to define a trustpoint:
crypto pki trustpoint DNAC_CA
enrollment url http://dnac-ip:80/
revocation-check crl

DNAC CA: The Automated Certificate Authority for Cisco DNA

Cisco DNA Center’s integrated CA simplifies PKI deployment at scale. Unlike traditional CAs, DNAC CA:

• Automatically provisions certificates to DNA Center-managed devices
• Generates device-specific certificates during onboarding
• Supports automated renewal before expiration
• Provides centralized visibility via DNAC GUI
• Uses ECDSA encryption for modern security standards

This eliminates manual certificate deployment, reducing configuration errors and operational overhead.

Configuring Trustpoints for DNAC CA: 5 Critical Steps

1. Prepare DNAC CA Certificate: Export the DNAC root CA certificate from System > Settings > Trusted Certificates in DNAC GUI
2. Define Trustpoint on Device: Configure the trustpoint with DNAC CA’s enrollment URL and imported certificate
   crypto pki trustpoint DNAC_CA
enrollment url http://<dnac-ip>:80/
crypto ca authenticate DNAC_CA
3. Generate RSA Keys: Create cryptographic keys for the device
   crypto key generate rsa modulus 2048
4. Enroll for Certificate: Request device-specific certificate from DNAC CA
   crypto pki enroll DNAC_CA
5. Verify and Apply: Confirm certificate installation with show crypto pki certificates and apply to interfaces/services

Best Practices for PKI Trustpoint Management

• Monitor certificate expiration dates via DNAC Assurance dashboard
• Enforce CRL checking to prevent compromised certificate usage
• Use separate trustpoints for different security domains
• Rotate CA certificates before expiration (DNAC automates this for device certs)
• Audit trustpoint configurations quarterly using DNAC’s compliance tools

Troubleshooting Common DNAC CA Trust Issues

If devices fail to trust DNAC CA:

• Verify NTP synchronization – time drift causes certificate validation failures
• Check DNS resolution of DNAC’s IP/hostname
• Confirm firewall allows traffic on port 80/443 to DNAC
• Validate root CA certificate hash matches on device and DNAC
• Use debug crypto pki for enrollment process diagnostics

FAQs: Crypto PKI Trustpoint and DNAC CA

Q: Can DNAC CA replace external CAs like Microsoft AD CS?
A: For Cisco device authentication, yes. However, for user certificates or non-Cisco systems, integrate with enterprise CAs via DNAC’s external CA support.

Q: How often does DNAC CA auto-renew certificates?
A: By default, DNAC renews certificates 30 days before expiration. This is configurable in Provision > Device Certificates.

Q: What happens if DNAC CA’s root certificate expires?
A: All issued certificates become untrusted. DNAC automatically rotates its root CA 1 year before expiration, but always monitor system alerts.

Q: Is DNAC CA FIPS 140-2 compliant?
A: Yes, when using DNAC hardware appliances with FIPS mode enabled and ECDSA keys.

Q: Can I use trustpoints with Let’s Encrypt certificates?
A: Technically yes, but DNAC CA integration provides automated lifecycle management that third-party CAs lack for Cisco environments.