ACA-Cloud1 Exam Dumps : ACA Cloud Computing Associate

 A is the correct answer because RDS provides whitelist access policies that allow you to set permitted IP addresses and IP network segments to effectively prevent hackers from attacking the server by port scanning. A whitelist is a security feature that specifies the IP addresses or CIDR blocks that are allowed to access your RDS instance. By default, the whitelist is empty, which means that no IP address can access your RDS instance. You can add IP addresses or CIDR blocks to the whitelist according to your business needs. You can also create multiple whitelist groups and assign different IP addresses or CIDR blocks to each group. This can help you manage the access permissions of different users or applications12

References: 1: Configure a whitelist 2: ApsaraDB RDS:Configure an IP address whitelist

 According to the Alibaba Cloud Academy, Alibaba Cloud provides powerful security services that are the same level of security services used to support Alibaba Group’s Double 11 Shopping Festival. However, you do not have to pay first before using any of the security services. Alibaba Cloud offers some security services for free, such as Anti-DDoS Basic, Server Guard, and Security Center Basic Edition. Other security services, such as Anti-DDoS Pro, WAF, and Security Center Enterprise Edition, are charged based on different billing methods, such as subscription, pay-as-you-go, or traffic-based. Therefore, the statement is false. References: Alibaba Cloud Security Services - Alibaba Cloud Security Course - Cloud Academy, Alibaba Cloud Security Pricing - Alibaba Cloud

 Alibaba Cloud CDN can directly accelerate the access to the files stored in OSS and reduce OSS traffic costs. Alibaba Cloud CDN is a global network of points of presence (POPs) that are distributed across the globe. Alibaba Cloud CDN serves to reduce back-to-origin traffic. This in turn prevents network congestion and reduces latency. If you use Alibaba Cloud CDN to accelerate access to OSS, you can benefit from the following advantages1:

• Improved user experience: Alibaba Cloud CDN caches the files stored in OSS to the POPs that are nearest to the users. This reduces the distance that the files need to travel and improves the access speed and user experience.
• Reduced OSS traffic costs: Alibaba Cloud CDN reduces the number of requests that are sent to OSS. This reduces the OSS traffic costs and the load on the OSS servers.
• Enhanced security: Alibaba Cloud CDN supports HTTPS secure acceleration and anti-leech protection. This ensures the security and integrity of the files stored in OSS. References: Use Alibaba Cloud CDN to accelerate access to OSS