DDoS (Distributed Denial of Service) is a type of cyber-attack in which multiple compromised systems are used to flood a target website, server, or network with an overwhelming amount of traffic, causing it to become unavailable to users. The goal of a DDoS attack is to overwhelm the target system's resources such as bandwidth, CPU, memory, and disk space, thus rendering it unable to respond to legitimate requests.

DDoS attacks are often executed using botnets, which are large networks of compromised computers or devices that are controlled by a single attacker. The attacker can use these botnets to launch DDoS attacks by sending a flood of traffic to the target system from thousands or even millions of different sources simultaneously, making it difficult to block or filter out the traffic.

DDoS attacks can cause significant damage to a target system or network, leading to financial losses, reputational damage, and even legal liabilities. To prevent or mitigate DDoS attacks, organizations can use various techniques such as network monitoring, traffic filtering, load balancing, and content delivery networks (CDNs).

There are several ways to avoid or mitigate DDoS attacks. Here are some of the best practices. See 1-6 below:

1. Use a DDoS Protection Service: A DDoS protection service can detect and filter out malicious traffic before it reaches your network or website. There are many third-party services available that can provide this protection, including cloud-based services, on-premises appliances, and hybrid solutions.

2. Implement Network and Application-Level Protection: Network and application-level protections can help protect against various types of DDoS attacks. Examples of these protections include firewalls, intrusion detection systems (IDS), intrusion prevention systems (IPS), and load balancers.

3. Use Content Delivery Networks (CDNs): CDNs can help distribute traffic across multiple servers and data centers, making it harder for attackers to overwhelm any single point in your infrastructure. CDNs can also help improve website performance by caching frequently accessed content.

4. Regularly Update and Patch Your Systems: Keeping your systems and applications up to date with the latest security patches and updates can help prevent DDoS attacks that exploit known vulnerabilities.

5. Use Rate Limiting and Traffic Filtering: Implementing rate limiting and traffic filtering can help prevent attackers from flooding your network or website with large amounts of traffic. These techniques can be implemented at various points in your infrastructure, including at the network perimeter, within the application, and within the database.

6. Have a Response Plan in Place: It's important to have a response plan in place in case of a DDoS attack. This plan should include steps for detecting, mitigating, and recovering from an attack, as well as a clear communication plan for notifying stakeholders and customers.