May 21, 2024

How to Prevent DDoS Attacks & What Must Be Done to Stop DDoS Attacks?

Dasha Korsik

Content Team Lead


DDoS Attacks: Definition, Types, How to Prevent Guide

Dasha Korsik

Content Team Lead


DDoS Attacks: Definition, Types, How to Prevent Guide

Website owners globally face a problem called DDoS (Distributed Denial of Service). A DDoS attack on a website allows hackers to close a working server for visiting. This is why preventing denial of service becomes a concern if you wish to avoid website downtime and financial losses.

In our article, you’ll discover some of the truly working DDoS attack detection measures and learn what to do to prevent DDoS attacks.

Introduction: What Is a DDoS Attack?

Do you know how much an hour of downtime costs for your business? According to Statista, the website owners reported an average hourly cost of their servers downtime as being more than 300 000 US Dollars. As today most businesses depend on data processing and providing users with unhindered access to a website or online services, applications or databases located on servers, they become extremely vulnerable to server attacks and focus on DDoS attacks prevention.

When a distributed denial of service attack happens, your website becomes unavailable due to overwhelming web traffic from different sources at the same time. It looks very similar to the situations your online store deals with on Black Friday, Christmas, and New Year eves, when accidental peaks of activity can make your store servers go down for some time.

The difference is that DDoS attacks are performed to crash your website’s infrastructure. Therefore your site becomes unavailable for an uncertain time, and your customers are not able to buy anything from you during that period.

What is more, DDoS attacks can go unnoticed for quite a long time, and you wouldn’t be able to provide customer support while your website or application is down. No sales, no feedback, drop-in visitors, and a damaged brand reputation is the result of a successful DDoS attack.

We have revised the measures preventing DDoS attack below, so stay tuned.

What Are the Types of DDoS Attacks and How To Prevent Denial of Service?

DDoS attacks come in the form of repetitive requests from different compromised IP addresses. IP blocking isn’t the cure, since there are too many of them to track, and sometimes they are hard to distinguish from legitimate traffic. Powerful servers are not the ultimate solution anymore, as internet access is coming to more and more devices, making it easier to plan knockdown attacks on websites.

What are the types of DDoS attacks?

If your website is attacked from a single device, then it is specified as a DoS attack, and in case your online store is attacked from several IP addresses, then it is a DDoS attack.

DDoS attacks include three major types:

  • Network layer (L3): DDoS attacks of this layer “work” over IP, DVMRP, ICMP, IGMP, PIM-SM, IPsec, IPX, RIP, DDP, OSPF, OSPF protocols. The targets of attacks are primarily network devices – switches and routers;
  • Transport layer (L4): impact is made via TCP and UDP protocols, as well as via DCCP, RUDP, SCTP, UDP Lite subprotocols. These attacks target servers and some Internet services, like gaming;
  • Application layer (L7): The attack is carried out at the application protocol layer. Most often, attackers use HTTP, HTTPS and DNS. Attacks of this level target both popular network services and various websites and web applications.

However, not everyone knows how to identify an attack and how can DDoS attacks be prevented.

How to recognize a DDoS attack?

When the actions of hackers become successful, this is immediately noticeable and is determined by problems and failures in the operation of the server or the portal located there, which is not covered by the protection against DDoS attacks.

DDoS attack signs include degradation in network performance, unavailability of websites, inability to access websites, and high volume of e-mail spam.

However, some signs help to recognize a DoS attack even at the initial stages:

  • Obvious interruptions with the operating system on the server. The computer shuts down incorrectly, and the server’s hardware capacity suddenly receives an unrelated load, easily distinguishable from daily indicators;
  • Incoming traffic is growing rapidly on one or more ports;
  • Monotonous actions of clients of a single portal are duplicated many times;
  • During the analysis of logs on network devices, you can identify requests of the same type from multiple sources related to one service. Particular attention should be paid to the sharp jump in the requests of the target audience, which was not previously noticed for your website.

What are the reasons for DDoS attacks?

Before learning how to avoid DDoS attacks, it is worth identifying the causes of the problem. DDoS attacks often target corporate servers of enterprises and Internet portals. Personal computers of individuals are much less likely to be attacked.

Nevertheless, if a DDoS attack on a certain Internet resource can be carried out with the aim of hacking and stealing server data, competition, fraud, or blackmail, then the reason for the attack on a personal computer is hardly predictable because it can carry anything: from personal hostility to “training” of novice hackers.

How To Avoid DDoS Attacks?

In a nutshell, preventing DDoS attacks aims at cutting off excess traffic that is directed through one channel or another. The simplest tools to prevent denial of service attacks filter traffic even before it reaches the server for processing. Moreover, simple hosting services that are the first to receive traffic from sites located on them can also be vulnerable.

So how to prevent DDoS attacks on websites? The DDoS prevention methods can be divided into passive and active, as well as preventive and reactive.

Below we offer 5 effective ways to prevent DDoS attacks.

1. L3-L4 network-level protection

The most common attacks occurring at the network level are L3-L4. At levels 3 and 4 operate protocols IP, ICMP, ARP, RIP, as well as TCP and UDP. Filtering DDoS traffic is considered to be a rational means of protection.

This method of preventing a DDoS attack is more commonly known as blackholing. However, this method blocks not only the dangerous traffic of cybercriminals but also the attempts of ordinary users to get to the web resource.

Therefore, as an alternative, you can limit the number of processed ICMP requests.

2. L5-L7 application-level protection

In some cases, more serious ways of stopping DoS attacks may be required. Attacks at levels 5-7 are more difficult to prevent.

Here it is important not only to quickly respond to the situation but also to keep the software up-to-date as many operating systems and software solutions from vendors already contain built-in tools for preventing DoS attacks.

3. Real-time protection

How to prevent denial of service in real-time? To provide this kind of protection, it is important to use a variety of tools offered by reputable developers. It all depends on the operating system of the servers and the implemented solutions.

For example, if a company has servers based on Cisco solutions, then it is worth entrusting this company with DDoS protection as well. Cisco offers a special  Cisco DDoS Protection Solution. Such software allows you to control traffic at all levels and cut off the artificial load of attackers.

Other vendors offer their views on how to prevent DDoS attacks. Cloudflare and Andrisoft provide efficient solutions for DDoS prevention.

4. Software companies offering denial of service prevention services

The costs of services for preventing denial of service attack start from several hundred US dollars for one-time protection. Complex work for DoS attack prevention in real-time will cost much more.

Large companies employ entire departments responsible for data security. They invest in package solutions from vendors we have already mentioned above.

5. How to prevent DDoS attack without migration?

The solutions for the remote protection of a website from external attacks are becoming extremely popular. It can be done without migrating the website and changing the hosting.

For example, you can use special services for the connection of an external IP address to redirect malicious traffic. Such a solution should be protected by WAF (Web Applications Firewall), and the protection process itself implies filtering traffic over the HTTP protocol.

NEKLO experts have collected some more useful recommendations for website owners on how to prevent denial of service attacks and reduce the losses from DDoS.

We suggest to:

  • Examine the logic of your product: starting from the development and testing phase, bugs and vulnerabilities can be detected and eliminated;
  • Maintain total control over the current versions of software and network services. It is recommended to use version control systems (Git) to rollback a project to a previous stable build;
  • Monitor access to network services. It is one of the most important solutions on how to prevent a DDoS attack. Provide multiple levels of access (master, guest, etc.) to the server’s network services and the project version archive. The list of persons who have access to server resources should be kept up to date;
  • Regularly scan the system for vulnerabilities: ask a software development company to offer any solution;
  • Flush DNS cache to prevent spoofing;
  • Use programs to prevent spam: hackers can direct their bots to fill in and send the same type of data to the server. To filter such traffic, the forms need to be converted to JS components or equipped with captchas and other validation tools;
  • Try a counterattack: redirect the attacker’s traffic to the attacker’s network;
  • Choose a hosting provider responsibly: carefully select a provider that guarantees protection against all modern threats. If you doubt your hosting provider is the right one, we have prepared a mini-guide to help you decide on a reliable hosting provider for your website.

DDoS attacks are not the only thing to be aware of. Learn how to improve computer security when working home as well.

Wrapping Up

Every year the “bad guys” find new ways to destroy the companies online. But as the number of attacks grows, new ideas on how to protect DDoS attack appear as well.

At NEKLO, we believe that “prevention is better than cure”. In case you are thinking of how to prevent denial of service attack on your website, our experienced specialists are ready to provide you with consulting services.

Just contact us through the form on our website. Together we will find the way to resolve related issues and help you answer the question how to avoid DDoS attack on your given website.