How Does a User Datagram Protocol (UDP) Work?
DP is a connectionless transport protocol, which means that it doesn’t spend time setting up a connection before sending data. Instead, a client can immediately send a request to a server. This request will include a port number that maps to the target application as well as the data and some other header information. When the server receives this request, it should reply with an appropriate response.
The connectionless design of UDP has its benefits and its drawbacks. The primary benefits of UDP are speed and efficiency. Since UDP performs no connection setup, data can get from point A to point B much more quickly than with other protocols. Also, the bare-bones approach to sending data reduces bandwidth consumption and overhead on the communicating devices.
However, UDP also has its downsides. With UDP, there is no guarantee that a packet will actually reach its destination. UDP is well-suited to use cases where latency is a greater concern than the occasional dropped packet.
Applications of UDP
UDP is ideally suited to applications where data is needed quickly, and the impacts of packet loss are minimal. The Domain Name System (DNS) is an example of a protocol that commonly uses UDP. Fast DNS lookups are essential to minimizing the latency of loading websites, and a client can always resubmit a new DNS request if the previous one doesn’t receive a response.
Other examples of protocols that often use UDP are videoconferencing and online gaming. In these contexts, low latency is critical to avoiding lag in video traffic. However, dropped packets will only cause the video or audio to freeze briefly and may be unnoticeable to the user.
TCP vs. UDP
The Transmission Control Protocol (TCP) is UDP’s counterpart. Both operate at the Transport layer of network models and specify the port and application where a packet should be directed.
TCP takes a different approach from UDP, prioritizing reliability over speed and efficiency. TCP connections are set up with a three-part handshake before any data is sent, and receipt of each packet is acknowledged by the recipient. TCP can offer greater reliability and error handling at the cost of higher overhead and increased latency.
How is UDP used in DDoS Attacks?
In a distributed denial-of-service (DDoS) attack, the goal of the attacker is to flood the target with more traffic than they can handle. One means of accomplishing this is sending requests to a service whose responses are larger than its requests. For example, DNS can be used in DDoS amplification attacks because requests are small, but responses may contain many DNS records associated with a given domain.
These attacks only work if the attacker can impersonate the target and pretend that the initial request originated from the target system. UDP is ideally suited to these types of attacks because there is no connection setup process like there is in TCP. An attacker can send a DNS request with a spoofed source IP address, and the response will be sent to the alleged sender, flooding them with unwanted traffic and data.
Security with Check Point Solutions
Check Point has extensive experience in ensuring that UDP network connections are secure and not malicious. Some examples of Check Point’s security capabilities for UDP traffic include the following:
- DNS Validation: DDoS attacks using DNS amplification result in a DNS response being sent to a target computer without a corresponding request. Check Point Firewalls apply zero-trust policies and track the state of UDP connections, ensuring that a DNS response entering the network matches a legitimate DNS request from one of the organization’s systems.
- AI-Enabled Detection: Check Point applies AI Deep Learning to detect and prevent sophisticated threats that use DNS, such as DNS tunneling and malware that tries to evade security by creating thousands of random domains.
- Optimized Network Routing: Quantum SD-WAN steers traffic by application over multiple links and monitors link performance to ensure UDP-based connections such as streaming content are not interrupted.
- DDoS Protection: Check Point DDoS Protector protects organizations from volumetric and application layer DDoS attacks that use the UDP protocol.
UDP traffic plays a vital role in providing many crucial services to the organization; however, it can also be unreliable and abused in various types of attacks. Learn more about how Check Point’s next-generation firewalls (NGFWs) can help your organization secure its DNS traffic with a free demo.
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