DDoS attacks are the most common type of network attacks, DDOS attacks are the following types.
1, TCP flood attack (the SYN Flood)
TCP flood attack is the most popular DoS (Denial of Service) and one of DDoS (distributed denial of service attack) way, this is a defect using TCP protocol, sending a large number of forged TCP connection request, commonly fake IP number or IP segments sent by the mass of the first handshake packet (SYN packet) requesting a connection, the second response handshake packet (SYN + ACK packet) attack the server, because the other side is the fake IP , the other party never receive the package and will not respond to third handshake. Leading to the attacked server keeps a lot SYN_RECV state of "semi-connected", and will retry the default response to five times a second handshake, stuffed TCP connections waiting queue, depletion of resources (CPU full load or insufficient memory), so that normal connecting the service request does not come.
2, reflective attacks (DRDOS)
reflective DDoS attack is a new variant of DoS, DDoS different, this method relies on the transmission data with the large number of victims IP address packet attacking host, then the host to attack IP address of the source to make a large number of responses, the formation of a denial of service attack. Hackers tend to choose those service pack is much larger than the response request packet to use, so that it can flow with less exchange for greater flow, obtain an amplified effect several times or even dozens of times, so skillfully deflected the question. In general, amplification may be utilized to do reflection DNS service attacks include, NTP service, the SSDP service, Chargen service, the Memcached like.
3, CC attack (HTTP Flood)
HTTP Flood, also known as CC attack, is in the seventh for the Web service layer protocol initiated the attack. By sending a large number of HTTP requests to the Web server to mimic the site visitors to deplete its resources. While some have HTTP flood attack can be used to identify and prevent their mode, but can not be easily identified. Its great harm mainly in three aspects: easy to initiate, filtering difficult and far-reaching.
4, direct attacks Botnet
Botnet is what we called "chicken" and now "chicken" is no longer limited to the traditional PC, more and more intelligent devices to market things, and security is much lower than PC, which makes the attack are more likely to get a lot of "chicken" and easier to launch direct botnet attacks. Depending on the type of botnet, an attacker can use it to perform a variety of attacks, not just the site also includes a game server and any other service.
More than four types of DDOS attack defense is the hardest type of attack, and when a website or server DDOS attack was either of them, are the need of high-level professional services can resist the anti-conventional defense measures in this four kinds of DDOS attacks before any action can hardly be alleviated. Internet companies must do ahead of protective measures in order to avoid DDOS attacks by the economic losses.
