H12-821_V1.0 Exam Dumps : HCIP-Datacom-Core Technology V1.0

By default, Huawei firewalls create security zones such as Trust, Untrust, and Local. The DMZ (Demilitarized Zone) is a security zone explicitly created by users. A DMZ is used to isolate an internal network from the external one, providing an additional layer of security by placing public-facing services (e.g., web servers) in this intermediary zone. This setup ensures that if a public-facing service is compromised, the internal network remains secure. Huawei Firewall configuration steps confirm this zoning principle, making DMZ creation an explicit user-driven action ​.

The correct command for configuring the VRRP (Virtual Router Redundancy Protocol) preemption delay is vrrp vrid 1 preempt-delay 20. This command sets the delay before a higher-priority VRRP router preempts the master role, ensuring stable operation during network transitions ​.

 LSA Lifetime and Deletion

The LS Age field in the LSA header tracks the age of an LSA. When the LS Age reaches its maximum value (3600 seconds), the LSA is marked for deletion. This ensures old or stale LSAs are removed from the network to maintain accurate routing information.

 HCIP-Datacom-Core Reference

Detailed explanation of LS Age behavior and LSA deletion processes can be found in the OSPF LSDB and LSA sections​​.