How can I detect if my server is under a DDoS attack (分布式拒绝服务攻击)?

Signs of a DDoS attack include a sudden surge in traffic, slow website loading times, server crashes, inability to access the website, and unusual network activity. Monitoring tools like network traffic analyzers, server logs, and intrusion detection systems can help identify suspicious patterns and confirm a DDoS attack. Pay attention to traffic originating from unusual geographic locations or using unusual protocols.