Huawei H12-821_V1.0 - HCIP-Datacom-Core Technology V1.0

Comprehensive and Detailed Step-by-Step Explanation:

DHCP Configuration Issues:

Option C:The DHCP function isdisabled by defaulton Huawei devices. If the administrator forgets to enable it, clients cannot receive IP addresses.

Option D:DHCP uses broadcast messages, which do not traverse routers. If the clients and DHCP server are on different subnets, aDHCP relay agentmust be configured.

Other Options:

Option A:Multiple DHCP servers can coexist as long as their IP address pools do not overlap. This is unlikely to cause the problem.

Option B:STP does not affect DHCP operations unless it delays port activation, which is uncommon in this scenario.

ï‚· IP Prefix List Matching Conditions

An IP prefix list matches based on:

Mask: Specifies the subnet mask length.

Action: Specifies whether to permit or deny.

Index: Orders the rules within the prefix list.

Port numbers are not applicable as matching conditions in an IP prefix list.

ï‚· HCIP-Datacom-Core Reference

IP prefix list configurations are detailed in the routing policy and route filtering chapters​​.

The output shows that the router with the IP10.0.12.2is the Backup Designated Router (BDR), as indicated in theState: BDRfield. The router ID is10.0.2.2, the interface cost is 1, and the IP address of the interface is10.0.12.2. Hence, C is the correct answer ​.

Comprehensive and Detailed Step-by-Step Explanation:

Switch Stack Overview:

In a switch stack, roles are assigned asmaster,standby, andslave.

The master handles configuration and control, while the standby serves as the backup master.

Behavior During Master Restart:

D:If the master switch restarts, the standby switch immediately takes over as the new master.

B:After the original master switch restarts, it becomes the master again (default behavior).

Incorrect Options:

A:The slave switch is not promoted to standby before the master switch restart completes.

C:The original standby switch remains the master after the restart.

Comprehensive and Detailed In-Depth Explanation:

SSH (Secure Shell)providessecure remote loginanddata encryptionover insecure networks.

A. TRUE→ SSH requiresuser authenticationbefore access is granted.

B. TRUE→ Enabling SSH openslistening ports, which could bescanned by attackers. Proper security measures (e.g., disabling unused SSH access) are recommended.

C. TRUE→ ACLs can be applied toVTY (Virtual Terminal) linesto restrict SSH access based onIP addresses.

D. FALSE→ The default SSH server port is22, not 23. Port23is used forTelnet, which isless securethan SSH.

📖Reference:Huawei HCIA-Datacom Study Guide, SSH Configuration and Security Measures.

Comprehensive and Detailed Step-by-Step Explanation:

Portal Authentication:

Portal authentication uses a web-based mechanism where clients are redirected to a login page.

Communication between the access device and Portal server uses HTTP or HTTPS protocols.

Correct Statements:

Option A:HTTP or HTTPS is used for Portal authentication.

Option D:Portal protocol packets are transmitted overTCPfor reliable communication.

Incorrect Statements:

Option B:Port 2000 is not the default for processing Portal packets.

Option C:The default destination port for communication with the Portal server is not 50100.

ï‚· IS-IS Interface Types

IS-IS interfaces are categorized based on physical link characteristics:

Point-to-Point (P2P): Direct connections between two routers.

Broadcast: Shared medium networks where multiple routers communicate.

ï‚· Incorrect Options

C. P2MP and D. NBMA are not standard interface classifications in IS-IS.

ï‚· HCIP-Datacom-Core Reference

IS-IS physical link classifications are elaborated in IS-IS link configuration sections​​.

Option B isfalse. By default, when the aggregate command is usedwithout any options, BGP generates asummary route, andsuppresses the specific routesthat fall under that summary. To advertise both specific and summary routes, you mustexplicitly configurethe detail-suppressed option to control whether specifics are suppressed or not.

Explanation of the other options:

Ais correct: When suppress-policy is specified, only specific routes matching the policy are advertised; others are suppressed.

Cis correct: The summary automatic command causes summarization based on classful boundaries, which is a legacy behavior.

Dis correct: With detail-suppressed, only the summary route is advertised, not specific prefixes.

Reference from Huawei HCIP-Datacom-Core Technology Study Guide:

“The aggregate command suppresses specific routes by default unless explicitly configured otherwise. Use of suppress-policy or detail-suppressed allows control over which routes are advertised.”

(Chapter: BGP Advanced Features – Section: Route Aggregation)

Comprehensive and Detailed Step-by-Step Explanation:

Single-Hop BFD:

Single-hop BFD is used for detecting link failures in directly connected devices.

It usesUDP port 3784for communication.

Multi-Hop BFD:

For multi-hop scenarios, BFD usesUDP port 4784to ensure end-to-end connectivity.

Incorrect Options:

TCP ports 3784 and 4784 (C and D):BFD does not use TCP.

Comprehensive and Detailed In-Depth Explanation:

STP Port Roles:

Root Port (RP)→ Connects directly to theRoot Bridge.

Designated Port (DP)→Forwards trafficfor a given segment.

RSTP introduces two additional rolesto improve redundancy:

Backup Port→ Aredundant Designated Port(on the same switch).

Alternate Port→ Abackup Root Port(path to the Root Bridge).

Allfour roles exist in RSTP, making the correct answerA, B, C, D.

📖Reference:Huawei HCIA-Datacom Study Guide, RSTP Port Roles and Rapid Convergence.