What is a DDoS Attack and How Do You Protect a Website Against One?
A DDoS attack (Distributed Denial of Service) tries to knock a website offline by flooding it with far more traffic than it can handle, sent from many machines at once, until real visitors can no longer get through. Protecting against one means filtering that malicious traffic out before it reaches your server, which is done with a mitigation layer that sits in front of the site and absorbs or blocks the attack. The practical goal is simple: keep the site available for genuine users even while an attack is underway.
What is a DDoS attack?
A Denial of Service attack aims to make a website or service unavailable. A Distributed Denial of Service attack does the same thing from many sources at once, often thousands of compromised devices acting together as a botnet, which makes it far harder to stop by simply blocking one address. The traffic is designed to exhaust something finite: the server's connections, its processing capacity, or the bandwidth of the network it sits on.
The key distinction from a normal traffic spike is intent and pattern. A busy sales day sends you more real visitors; a DDoS attack sends you traffic whose only purpose is to consume resources and crowd out those real visitors. According to Cloudflare's DDoS threat reporting, attack volume has risen sharply year on year, and the largest recorded attacks are now measured in the terabits per second, well beyond what any single unprotected server can absorb.
How does a DDoS attack actually work?
Most attacks fall into three broad types, and it helps to know which is which because they are defended differently.
Volumetric attacks are the brute-force kind: they saturate your available bandwidth with sheer volume, like a UDP flood, so nothing else can get through. Protocol attacks target the way connections are set up, exhausting server or firewall resources with things like SYN floods that open connections and never complete them. Application-layer attacks are the quietest and often the hardest to spot: they mimic real user behaviour, sending requests that look legitimate but are aimed at the most expensive parts of your site, such as a search or login endpoint, until the application buckles.
What unites all three is that they overwhelm a resource. The defence, in every case, is to identify and remove the malicious traffic before it reaches the resource being targeted.
What does a DDoS attack cost a business?
The obvious cost is downtime: while the site is unreachable, visitors cannot book, buy, or contact you, and for a healthcare or clinic site that can mean patients unable to reach care information or appointment forms. Industry estimates commonly put the cost of unplanned web downtime in the thousands of euros per hour for a transacting business, though the real figure depends entirely on what your site does for you.
The less obvious costs matter too. There is the reputational hit of a site that is visibly down, the staff time pulled into firefighting, and in some cases a DDoS attack used as a smokescreen to distract from a second intrusion attempt. For a regulated or patient-facing organisation, an outage also raises availability and continuity questions that go beyond lost revenue.
How does DDoS mitigation keep a site online?
Effective mitigation puts a filtering layer between the internet and your server, so traffic is inspected before it ever reaches you. Legitimate visitors pass through; traffic that matches attack patterns is absorbed or dropped at the edge, across distributed infrastructure with far more capacity than a single origin server.
This works best as an always-on layer rather than something switched on mid-attack, because the first minutes of an attack are when the damage is done. A mitigation service sees the traffic first, recognises the signatures of the attack types above, and scales to absorb volume that would overwhelm your own hardware. At EuroraCloud the DDoS mitigation runs from our decentralised infrastructure across the Netherlands, France, and Germany, which keeps traffic within Europe for data-sovereignty and latency reasons while providing the capacity to absorb large attacks.
What should you do next?
Start by knowing whether you currently have any mitigation layer at all, since many websites are protected only by their hosting provider's defaults, which are often thin. If an attack today would take your site offline, that is the gap to close, regardless of whether you have ever been hit before, because the point of mitigation is that it is already in place when an attack starts.
If you would like to see where your own site stands, EuroraCloud can review your current setup and show you what our mitigation resolves. See what EuroraCloud resolves
Conclusion: what should you take away about DDoS protection?
A DDoS attack does not need to breach anything to hurt you. It simply makes your site unreachable, and for a business that depends on its website to inform, book, or sell, an hour offline is a real cost. The three attack types work differently, but the answer to all of them is the same: a mitigation layer in front of your site that filters malicious traffic before it lands. The single most useful thing you can do is check whether that layer is already in place today, because mitigation only protects you if it is running before an attack begins, not after.