CCTA cheat sheet
CCTA · Keep the key ideas within reach.
Evidence, packet captures, and a bounded troubleshooting method
Define the exact failing flow and information cutoff.
Use packet, policy, process, and application evidence together.
Bound captures and debug collection by scope and stop conditions.
Retest the original symptom and document the result.
Routing, state, access policy, NAT, and the return path
Separate routing permission from security-policy permission.
Track original, translated, and return-flow tuples.
Check path symmetry and state where relevant.
Validate topology and the specific cause before weakening protection.
Management access, trust, policy installation, and logging
Distinguish console access, trust, installation, and forwarding.
Validate the specific SIC failure before considering reinitialization.
Confirm publication, compilation, target installation, and enforced version separately.
Trace logging from event generation to the actual query result.
VPN negotiation, encryption domains, and tunneled traffic
Separate negotiation success from application delivery.
Compare identities, credentials, proposals, selectors, and routes.
Distinguish outer encapsulation from inner application traffic.
Validate both directions and avoid unscoped association resets.
Cluster state, synchronization, resource trends, and safe recovery
Interpret roles in the configured cluster mode.
Correlate synchronization, interface health, and policy readiness.
Plan failover tests around actual existing applications.
Use baselines and rates to locate resource constraints.