A denial of service attack is a computer network attack in which the attacker seeks to disrupt a network or system resource by either temporarily or permanently disrupting services of an IP-based host connected to the internet. When a host’s system is infected with the malicious software used to initiate the attack, it will cease to work, or at least not properly function as expected.
The attacks can come from an IP-based attacker or a remote network of IP-based attackers who have co-opted a host’s system for their own purposes. Usually these attacks are done through the use of data packets (also called as packets of commands) that pass between computer networks of computers.
Denial of Service attacks usually take the form of a series of messages that are sent to an IP-based host which causes the host to stop processing requests or respond to requests in a certain manner. These messages are sent in various ways and include ICMP and UDP packets.
An attack may also be a network-wide attack. This means that if a single host is attacked, the attack will also affect other hosts in the network. A common example of this is when a number of firewalls are installed in a particular network. If any of them is taken out, the attacks will affect all the other firewalls and the entire network.
Denial of Service attacks are sometimes carried out by a human intruder, but sometimes they are done by a computer itself. There are many reasons that computers may become infected by malicious software, such as when an individual a rogue piece of software from a removable media such as CD, DVD, USB, or Blu-ray disc. Sometimes a computer infected by this type of malicious software can simply be subjected to a more sophisticated attack like a DDoS, where the attackers to flood the internet with massive amounts of network traffic, which can make the host’s system difficult to handle.
The most common types of attacks against servers, such as servers and web-hosting servers, are Distributed Denial of Service (DDoS), and Flooding. The former attack attempts to bring down a server by sending large numbers of “ping”brick” packets, whereas the latter attack attempts to bring down a server by flooding the network resources. The most common reason for using a DDoS or Flooding attack is to bring down a server and the main reason is because the web server is being used by a website and is hosting many customers’ websites.