A DoS (denial of service) is a cybersecurity attack in which an attacker intentionally floods the resources of a service or network to prevent access or access to the service by real users. DoS attacks are often designed to overload servers, networks or websites, resulting in their response time being slowed or even eliminated.
Glossary
A domain name is a unique, easily remembered address used to access websites, such as "cert.hu" or "google.com". Users can connect to websites using domain names through the DNS system.
The DNS system is basically the internet's "phone book", a database in which domain names are assigned to IP addresses. It is a distributed system, i.e. there is not a single DNS database, but countless DNS servers around the world, which are in a hierarchical relationship and are able to communicate with each other. Its primary task is to translate a domain name that humans can understand into an IP address that network devices can understand, or vice versa (reverse DNS), so that a given resource can be found on the network.