DoS (denial-of-service attack) or DDoS distributed denial-of-service attack

As most of us know what DDos is! Last week dhiraagu got hit hard by DDos attack. It took 9 days to restore their network back to normal working condition. As told by dhiraagu, they attacked Dhiraage Web Servers & Main Router.

So what DDos?
The use of a DDos is to overwhelm or flood servers, network links, and network devices (routers, firewalls, etc.) by sending segments/packets and making its resource/bandwidth busy or unavailable for Intended Users.
A DDoS attack directs hundreds or even thousands of compromised "zombie" hosts against a single target. These zombie hosts are unwittingly recruited from the millions of unprotected computers accessing the Internet through high-bandwidth, "always-on" connections. By planting "sleeper" codes on these machines, hackers can quickly build a legion of zombies, all waiting for the command to launch a DDoS attack. With enough zombie hosts participating, the volume of an attack can be astounding. The diagram show how DDos work.



Can we Protect Network from DDos!

Yes / No. DDoS is emerging as the weapon of choice for hackers, political "hacktivists," cyber-extortionists, and international cyber-terrorists. Easily launched against limited defenses, DDoS attacks not only target individual Websites or other servers at the edge of the network- they subdue the network itself. Attacks have begun to explicitly target the network infrastructure, such as aggregation or core routers and switches, or Domain Name System (DNS) servers. Because DDoS attacks are among the most difficult to defend against, responding to them appropriately and effectively poses a tremendous challenge for all Internet-dependent organizations. Network devices and traditional perimeter security technologies such as firewalls and intrusion detection systems (IDSs).

Some DDoS attacks Incidents

'Anonymous' group attempts DDoS attack against Australian government (September 9th, 2009)
Twitter & Facebook Taken Offline By DDoS Attacks (August 6th, 2009)
U.S. eyes N. Korea for ‘massive’ DDOS attack (July 8th, 2009)
GoDaddy hit by a DDoS attack (January 16th, 2009)
DNS Backbone DDoS Attacks (October 22nd, 2002)