H12-821_V1.0 Exam Dumps - Huawei HCIP-Datacom Questions and Answers

In a stateful inspection firewall, if the status detection mechanism is enabled, it tracks and validates the state of connections using the session table. If there is no session table and a SYN+ACK packet reaches the firewall, it checks the security policy. If the policy explicitly permits the packet, it will pass through the firewall, but no session table will be created without the initial SYN packet. The other options are either incorrect or misrepresent the behavior of stateful inspection ​.

Comprehensive and Detailed Step-by-Step Explanation:

DHCP Configuration Issues:

Option C: The DHCP function is disabled by default on 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, a DHCP relay agent must 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.

Comprehensive and Detailed In-Depth Explanation:

A. TRUE → If preemption is enabled , a higher-priority router can take over as the Master .

B. TRUE → If preemption is disabled , the current Master remains active even if a higher-priority router joins.

C. TRUE → The Master router sends VRRP Advertisement packets to maintain its role.

D. FALSE → If a VRRP router is the IP address owner , it automatically becomes the Master without needing to participate in an election .

???? Reference: Huawei HCIA-Datacom Study Guide, VRRP Priority and Preemption Mechanisms.

A stateful inspection firewall tracks the state of active connections. If a packet matches an existing session in the firewall ' s state table, it is allowed to pass. The diagram indicates that the TCP packet matches the session state, so the firewall forwards it ​.

All four are valid reasons why IKE (Internet Key Exchange) negotiation might not be triggered:

A – Security policy mismatches can block data flows , preventing IPsec from initiating.

B – If the route to the peer is unreachable , no packets can reach the tunnel interface, and IKE will not start.

C – If the IPsec policy is not bound to the correct interface , no protection is triggered.

D – If the ACL does not match the actual traffic , the flow will bypass IPsec.

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

“Common causes of IKE negotiation failure include incorrect ACLs, misapplied policies, unreachable peers, and misconfigured security zones.”

(Chapter: VPN Technologies – Section: IPsec Troubleshooting)

BFD control packets are encapsulated in UDP packets, and the destination port number for multi-hop BFD control packets is 4784. This is a standardized port for multi-hop BFD operation ​.

When two BGP peers negotiate the Hold Time, the shorter value between the two configured Hold Time values is selected. This ensures compatibility and maintains the stability of the BGP session ​.

 ACL Modification

Named ACLs can be modified after their creation. Unlike numbered ACLs, named ACLs provide greater flexibility for editing individual rules without deleting the entire ACL.

Therefore, the statement is incorrect.

 HCIP-Datacom-Core Reference

The flexibility and editability of named ACLs are discussed in the ACL configuration sections​​.

In IPv6 , fragmentation is handled only at the source node . Intermediate routers do not fragment packets . Instead, if a packet is too large for the next link, the router sends back an ICMPv6 Packet Too Big message to the source, which then adjusts its packet size.

This design:

Reduces processing load on intermediate devices.

Supports Path MTU Discovery (PMTUD).

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

“In IPv6, routers do not perform fragmentation. Only the source device fragments packets if needed, based on ICMPv6 feedback.”

(Chapter: IPv6 Fundamentals – Section: Fragmentation and PMTUD)