DoS (Denial of Service) attacks have some characteristics that help distinguish and identify such attacks:

　　Bandwidth consumption:

　　DoS attacks are designed to exhaust the bandwidth resources of the target system. The attacker sends a large number of requests, occupying the network bandwidth of the target system, causing legitimate users to be unable to access services normally.

　　Resource exhausted:

　　Attackers try to exhaust the target system's key resources (such as CPU, memory, disk space) by sending malicious requests or occupying system resources. This results in degraded system performance and may even cause a system crash.

　　Frequent connection attempts:

　　DoS attacks usually involve a large number of frequent connection attempts, such as a large number of TCP connection requests. An attacker may use automated tools or worms to generate more connection requests than a system can handle.

　　Single source:

　　DoS attacks usually come from a single attack source or a small group of attack sources. An attacker may use a single host or a small number of hosts to launch an attack in an attempt to render the target system unavailable.

　　​Short-term persistence:

　　DoS attacks are usually short-lived and sustained. An attacker may send a large number of requests for a short period of time, then stop and launch the attack again to bypass the target system's defenses.

　　​Easy to detect:

　　Because DoS attacks usually have certain characteristics, such as large amounts of network traffic, frequent connection attempts, etc., they are relatively easy to detect. Network administrators can use monitoring and intrusion detection systems to identify these types of attacks.

　　IP address forgery:

　　Attackers may use IP address spoofing technology to try to hide the true source of the attack. This makes it more difficult to trace and stop attackers.

　　No authorized access:

　　A DoS attack is an unauthorized behavior in which an attacker attempts to deprive legitimate users of service access by exceeding the system's processing capabilities.

　　Understanding these characteristics can help network administrators better identify and respond to DoS attacks. In terms of preventing DoS attacks, adopting appropriate network security measures, intrusion detection systems and DDoS protection services are key defense methods.