The shop that went quiet
A small online shop has its busiest day. At noon the website slows down. At 12:10 it will not load at all.
The staff check the sales. There are none. Yet the server is working as hard as it can.
Something is sending it far too many requests.
By the end of this lesson
Note
I can say how to spot a denial-of-service attack from the traffic.
Key words
| Word | What it means | Example |
|---|---|---|
| Denial-of-service | an attack that overloads a service so nobody can use it | DoS |
| Distributed attack | a denial-of-service attack from many computers at once | DDoS |
| Request | one message that asks a server for something | |
| Traffic | all the messages moving on a network | |
| Network | computers joined so they can share data | |
| IP address | the number that names a device on a network | 203.0.113.7 |
| Outage | a time when a service is down |
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DoS and DDoS overload a service
A denial-of-service attack tries to overwhelm an online service so it stops working for real users.
A distributed one, a DDoS, uses many computers at the same time, all aimed at one service. Those computers are often devices an attacker has taken over.
Four signs in the traffic
| Sign | What you see when you monitor the traffic |
|---|---|
| Degraded performance | Pages load slowly and everything lags |
| Increased traffic | A sudden jump in the number of requests |
| Many requests from one address | The same IP address appears again and again in the log |
| Outage | The website cannot be reached at all |
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3 questionsYour answers are marked here and are not kept. A college account keeps every student’s marks.