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

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.

The MED (Multi-Exit Discriminator) is an optional, non-transitive attribute used to influence the exit path. MED is considered after attributes such as Local-Preference, AS-Path, and Origin during route selection. By default, if a MED value is missing, it is treated as 0 unless thebestroute med-none-as-maximumcommand is configured to treat it as 4294967295 ​.

The correct command for configuring the VRRP (Virtual Router Redundancy Protocol) preemption delay isvrrp 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 ​.

Comprehensive and Detailed in-depth Step-by-Step Explanation:

BGP (Border Gateway Protocol) uses specific message types to establish and maintain peer relationships between routers. The primary BGP messages involved during the establishment and maintenance of peer relationships are:

Open (D):

The Open message is the first message sent after a TCP connection is established between BGP peers.

It is used to exchange parameters such as the AS number, BGP version, hold time, and BGP identifier.

Keepalive (A):

After the Open message exchange, Keepalive messages are sent periodically to maintain the BGP session.

These messages confirm that the connection is still alive.

Update (C):

Update messages are used to exchange routing information after the peer relationship is established.

They contain information about network prefixes and their associated path attributes.

Hello (B):

Hello messages are not used in BGP. They are typically used in protocols like OSPF or IS-IS to establish and maintain neighbor relationships.

Thus, the correct answers areA (Keepalive),C (Update), andD (Open).