Huawei Updated H12-821_V1.0 Exam Questions and Answers by eshaal

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 ​.

Comprehensive and Detailed In-Depth Explanation:

IP Prefix lists are used to filter routes based on prefix and mask length.

The optional parameters include:

Index of the prefix list → Specifies priority/order (Optional).

Shortest mask length to be matched → Defines the minimum subnet mask (Optional).

Longest mask length to be matched → Defines the maximum subnet mask (Optional).

Mask length (D) is mandatory because it specifies the exact prefix length being matched.

???? Reference: Huawei HCIA-Datacom Study Guide, Configuring Prefix Lists for Route Filtering.

ICMPv6 messages are classified into two types: error messages (e.g., Destination Unreachable, Time Exceeded) and informational messages (e.g., Echo Request, Echo Reply). This classification is fundamental to ICMPv6's operation ​.

The sequence of steps for electing the root port in an STP (Spanning Tree Protocol) network is as follows:

Bridge ID Comparison: The Bridge ID (BID) is compared between the bridges in the network. A smaller value indicates a higher priority, meaning the bridge with the lowest Bridge ID is elected as the root bridge.

RPC (Root Path Cost) Comparison: The path cost to reach the root bridge is calculated. The router with the lowest Root Path Cost (RPC) to the root bridge will have a higher priority for the election of the root port.

Peer BID Comparison: If there is a tie in the Root Path Cost, the Peer BID is compared. A smaller Peer BID indicates a higher priority. This step ensures that if two routers have the same RPC, the one with the lower Peer Bridge ID wins.

Local BID Comparison: If there is still a tie, the Local BID is compared. A smaller Local BID indicates a higher priority. This final step ensures that the router with the lowest local identifier is selected.

Bridge ID Comparison:The first step in electing the root port is comparing the Bridge IDs. The bridge with the lowest Bridge ID becomes the root bridge. The Bridge ID is made up of the bridge priority and MAC address. The root bridge is the center of the network for STP, and all other ports will calculate their paths based on this root.