How to deal with denial of service attacks


Learn all about Denial-of-Service (DoS) attacks and what you can do to protect against them.

What is a Denial-of-Service attack

This is a form of malicious attack that attempts to make a machine, network resource or website unavailable by overloading the target system with traffic. There are 2 types of malicious attack that fit the category:

  • A Denial-of-Service (DoS) attempts to overload the target system with traffic from a single IP address.

  • A Distributed Denial of Service (DDoS) attack involves thousands of users generating traffic from multiple IP addresses at the same time to overload the target.

Types of DDOS attacks

There are three main types of DDoS attack:

Volume-based attacks overwhelm a server or website with massive amounts of bogus traffic.

Protocol or network-layer attacks target network infrastructure with large numbers of packets, or slow or malformed pings.

Application-layer attacks target apps directly, rather than the underlying infrastructure, by flooding it with maliciously crafted requests.

How do I know if I'm being DDOS?

DDoS attacks can cause the victim to experience slow speeds or a loss of Internet connection, but can also cause entire websites, apps or businesses to go offline.

What can I do if I’m a victim of a DOS attack?

If you are the victim of a Denial-of-Service attack, you should raise a complaint with the Internet Service Provider (ISP) that owns the IP addresses the attacks are being made from. To find the ISP, you’ll need to look through the Hub’s Firewall and Network logs and pick out the IP addresses that have sent excessive traffic your way.

To identify the ISP you need to contact, you can use Whois (and Ping.eu can help too). Simply enter and search the IP addresses that have been sending the excessive requests, and the site will tell you which Internet Service Provider owns them. In most cases, a Whois search will also provide the ISP’s contact details. You can then get in contact directly and raise a complaint.

Denial of Service attacks alert

You might have received a letter or email from Virgin Media about malicious traffic that has originated from a device on your home broadband connection. If you have, there’s no need to worry. The advice on this page should help sort things out.

How to prevent or stop Denial-of-Service attacks

If you have a basic knowledge of computers and connected devices, there are some steps you can take to secure your email inbox and home network. Please follow the steps below*:

Check your routers firewall settings

The most common cause of this type of problem is through a misconfiguration in your router’s firewall settings.

To check the firewall rules, find your broadband router from the options below and follow the steps:

Make sure all your devices are protected by a firewall

It is important to check all your devices sit behind a firewall. In most cases your firewall is configured as a part of your router – and this is the case with the Virgin Media Super Hub and Hub 3. If you have specifically disabled the Firewall in your router, it is crucial that you configure your device so it is protected by a firewall.

Check your device for viruses

If you have not identified any issues through the firewall steps, then it is likely that a device on your home network is infected with malware that is participating in online abusive activity. We recommend running anti-virus scans across all your devices to detect and remove any infections.

If you have an existing security package installed, please consult the instructions on how to remove infections from your device. If you do not have an existing anti-virus, virgin media internet security can help protect your devices from malicious software.

Get up-to-date software
Keep your operating system and application software up-to-date and install software patches so attackers can't take advantage of known problems or vulnerabilities. Many operating systems offer automatic updates. If this option is available, you should enable it.

Denial-of-Service attacks FAQ

Need more help with Denial-of-Service attacks? Check out our FAQs below:

Where can I find more help and support with DoS or DDoS attacks

If you’d like further advice, then our forum community will be happy to help. Just visit our online community and join the conversation on our Security Matters board. You can also find general security advice and articles on other vulnerabilities by checking out the Security Hub.

If you want to learn more about staying safe online, browse our online security articles.

*These fixes are provided as a courtesy and we are not responsible for any problems encountered whilst applying these steps and we are not able to provide any technical support for such problems.

Has this helped?