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Effective Countermeasures To Protect Your Server Against DDOS Attacks
Servers are the backbone of the Internet. They are what websites and web resources are hosted on. By communicating with the server, a client can access the resources on it.
However, servers are also a very attractive target for hackers. An attack on a server could have many different purposes, but the most common is either the stealing of data or compromising the server’s function.
A popular way of doing the latter is using DDOS attacks. DDOS stands for Distributed Denial of Service. A DDOS attack aims to overwhelm the server with so many requests that its resources get stretched so thin that it can’t deal with any requests.
Today, we will check out how to protect your servers from DDOS attacks.
Methods to Safeguard Your Servers Against DDOS Attacks
Given below are some solutions for preventing DDOS attacks on your servers.
1. Limit the Attack Surface Area
The attack area refers to how many global regions the servers can take requests from. The more areas they can entertain, the higher the attack surface area.
Limiting the surface area quite literally reduces the power of DDOS attacks. After all, you are automatically ignoring all requests that are coming from outside a designated zone. No matter how numerous they may be, they will not be entertained thus keeping the server resources free.
To limit attack surface area, you can use geofencing. Geofencing is a technology that creates a virtual boundary around a physical location. This location can be as big or as small as you want it to be.
The point of geofencing is to only allow the requests from within the designated area. So, how do you check which requests are coming from which area? There are a number of ways to do that. The easiest is to use IP geolocation.
IP location technology lets you determine an IP address’s location to a very high degree (think street address). You can enforce geofencing by setting up a system that checks the IP addresses of incoming requests and does an IP location lookup.
2. Real-Time Threat Monitoring
Network traffic is chaotic but there is some method to the madness. You can set up real-time monitoring systems to check network traffic.
The main issues you are going to look for are:
- Sudden spikes in network traffic
- Detection of signatures associated with DDOS attacks
- Historical traffic analysis
There are plenty of ways in which you can analyze network traffic. For example, a tool like Wireshark can help you capture network packets and analyze them to get a detailed view of the traffic.
Servers, switches, routers, and even firewalls create logs of all traffic they deal with. You can retrieve those logs to find anomalies in your network traffic.
There are also other tools like NetFlow by Cisco that collect and provide summarized data about network traffic flows. This data contains info about:
- Source and destination IP addresses
- Ports
- Protocols
- Amount of data being transferred
With the help of such tools, you can monitor your server in real-time to protect it against DDOS attacks.
3. Utilize CDNs and Caching
CDNS or content delivery networks and caching are a great way of dealing with overwhelming server traffic. Let’s analyze the advantages of this approach.
So, a cache is a temporary storage that is usually closer to the client than the server. Most browsers nowadays have caching support, and they will often store data for websites that you frequently visit. This enables faster loading because most of the data is available on the device, and very little data needs to be transferred from the server.
With CDNs, you can extend caching support to a lot more people. A CDN is basically another server that is geographically closer to your end users. It caches a lot of the resources available on the main server and provides them quickly to clients in its vicinity.
CDNs have the obvious advantage of reducing the strain on the main server. In the event of a DDOS attack, much of the brunt will be borne by the CDNs, thereby saving the main server from crashing. In the meantime, you can take more active measures to stop the attack.
4. Use Rate Limiting
Rate limiting is an active mechanism for defense against DDOS attacks. This is a very straightforward approach. You disable the server from entertaining any more requests than it is capable of dealing with.
So, that means any requests that come after the limit is reached are just dropped instead of being put in a buffer. The advantage of this method is that DDOS attacks won’t kill your server. The disadvantage is that genuine requests may also get dropped this way.
That’s why the best way to use this technique is with other active techniques like real-time threat monitoring. That way, you can isolate and remove the DDOS traffic without letting your server go down.
5. Utilize Anycast Network Diffusion
Another way of avoiding DDOS attacks is to use anycast network diffusion. Similar to CDNs, this is an approach that prevents the “origin server” from getting overloaded with requests.
To use anycast, it is important that you have multiple data centers that can cater to requests and take the load away from the origin server.
So, how does Anycast work? In anycast network diffusion, all requests for a particular IP address associated with a server are entertained by multiple data centers.
Which data center entertains the request is typically dependent on the client’s latency with each center. Usually, the lower latency data center has to deal with the request.
In the case of a DDOS attack, you have more time before your resources get overwhelmed, and you can apply active measures to mitigate the attack.
6. Web Application Firewalls
Firewalls are software solutions that help to detect network threats and prevent them from infiltrating your infrastructure.
A Web Application Firewall (WAF) is a special type of firewall that can block malicious traffic between web apps and the internet. It does so by using customizable policies to inspect traffic and block malicious requests.
A WAF running on a server will automatically filter requests that do not meet specific security criteria. A DDOS attack would need to be highly sophisticated to bypass a WAF. Even then, you can update the WAF in real time to change its filtration criteria.
So, WAFs are a good software solution for preventing DDOS attacks.
Conclusion
DDOS attacks are a constant headache for website owners. Most DDOS attacks don’t even happen due to some good reason, they just occur because the attacker can do it.
In this article, we discussed some ways of preventing and mitigating DDOS attacks. Utilize these methods to keep your servers safe from such harmful attacks.
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