Intermediate Topic 28 of 51 Security & Cryptography
Denial of Service
Overwhelming a service to make it unavailable.
How it works
DoS floods or exhausts resources (bandwidth, connections, CPU); DDoS uses many sources. Defenses: rate limiting, CDNs, scrubbing, SYN cookies and autoscaling.
Where it is used
Targeting availability.
Common pitfall
Amplification attacks (DNS, NTP) abuse open servers.
Where it fits in the course
Denial of Service is topic 28 of 51 in Security & Cryptography, rated Intermediate. It follows Buffer Overflow. The next topic is Man-in-the-Middle Attacks.
Practice and explore
- Open the interactive lesson, with a mini quiz.
- Take the Security & Cryptography quiz.
How to study this topic
- Read the explanation above and restate the definition in your own words.
- Open the interactive lesson and answer its mini quiz.
- Read the common pitfall, then write a short example that avoids it.
- Check your understanding in the Security & Cryptography quiz, and revisit the topic if you miss a question.
Frequently asked questions
What is Denial of Service?
Overwhelming a service to make it unavailable. It belongs to Security & Cryptography and is an intermediate-level topic.
Where do people use Denial of Service?
Targeting availability.
What is the most common mistake with Denial of Service?
Amplification attacks (DNS, NTP) abuse open servers.
What should I learn before this topic?
Start with Buffer Overflow, the topic just before it in Security & Cryptography.
How can I practice it?
Answer the mini quiz in the interactive lesson, then take the Security & Cryptography quiz.
Is Denial of Service hard to learn?
It is an Intermediate topic. Be comfortable with the Beginner topics in this area first, then read the common pitfall carefully, since it is where most mistakes happen.
How long does it take to learn Denial of Service?
Most learners can read the explanation and finish the interactive lesson in under an hour. Fluency comes from applying the idea, so plan a few short practice sessions with the quiz.
Which topics are related to Denial of Service?
Buffer Overflow, Man-in-the-Middle Attacks, CSRF are closely connected. The full list is in the related topics section of this page.
What should I study after Denial of Service?
Continue with Man-in-the-Middle Attacks, the next topic in Security & Cryptography.
Related topics
- Buffer Overflow (Security & Cryptography)
- Man-in-the-Middle Attacks (Security & Cryptography)
- CSRF (Security & Cryptography)
- Network Intrusion Detection (Security & Cryptography)
- Service Discovery (Distributed Systems & Cloud)
- Service Mesh (Distributed Systems & Cloud)
- Service Workers (Web Development)