Today i will you briefly explain that What is the difference between a DoS and DDoS?
TWO: Denial of Service (Denial of Service)
A web server is able to with stand a certain amount of concurrent requests or connections. If you exceed this connection limit, two things can happen:
1) The response of user requests can be slow or nil
2) Server network disconnects and goes offline.
Saturates the server using many requests for the same PC that is slowly consuming resources until it begins to reject requests and began to refuse service (DoS) .
An advantage is that the administrator can see where all these attacks come, bans the IP and ceases attack … This attack is done with desktop-style programs like this that you can see in the picture:
In which an IP is placed and the power of attack and go.
The use of such programs in the hacking is frowned upon, since only give misuse, that is, use it to pull websites. As this, there are various other programs and there are few who give them to good use such programs. A good use would be to perform a load or stress test, to see how much traffic could bear a website.
DDoS: Distributed Denial of Service (Distributed Denial of Service)
This is similar to the DoS attack, as this type of attack is also in pulling the server. The difference is that this attack is distributed. This means that not attacked from a single PC and the DoS, but there are many PCs, making requests to the same server. The webmaster can not know where the attack is coming, so it costs more to stop it. This is called the Distributed Denial of Service (DDoS).
This type of attack (DDoS) is made with a Zombie network. In other words, it becomes a Botnet.
In both cases what is sought is to consume the bandwidth of the server to pull the web.
It’s obviously much more powerful attack with a Botnet as are several PCs which strikes an . single site This attack is done with desktop software very similar to the Trojans (both client and server are executable), there are also web panel and finally by IRC. Then some screen panels botnets: IRC
In all cases, the propagation methods are equal. A case very seen, are the flashy videos facebook.
When infected, then we infectaremos our contacts and so on to form a chain with a large number of infected.
There are more ways of infection, such as web:
When you open or run any of these, you’re likely to end up infected with a botnet and our connection would be used to attack sites.
How to prevent attacks?
As webmasters we can install on our server the famous mod_evasive
Basically what it does is keep a PivotTable with URIs accessed by different clients IP Apache, and allows you to run some actions when the same IP requesting the same resource (same URI or items in one spot) over n times in m seconds. The default action is running the mod_evasive once exceeded the maximum requests per second allowed, blocked for a number of seconds the client (the IP) returning a 403 error (Forbidden) to the HTTP request. But the interesting thing is that it also lets you run a command system when registering an attempted attack, which can add a rule to iptables to block IP client. Another way is using Cloudflare which is a free system that acts as a server “proxy” between visitors and our server. By acting as a “proxy” CloudFlare caches (stores in memory) static content of its website, which reduces the number of requests to our servers, but still it allows visitors access to its website. There are several advantages of the CloudFlare system.
Improved Performance Web: CloudFlare has “proxy” servers located around the world. The “proxy” servers are located close to its visitors, which means they notice improvements in loading time of a page, since the content “caching” is delivered from the nearest server “cache” rather than directly from our server . Many studies show that much faster is a web visitors stay longer in it.Protection against comment spam (Spam).
CloudFlare leverages data from third-party resources to reduce the number of comments “spam” on its Web Alert Visitors of infected computers: alert CloudFlare human visitors with an infected computer and need to take appropriate action to clean the “malware” or viruses from your computer actions. Visitors must enter a CAPTCHA (visual set of numbers and letters) to access its website.
Offline Navigation Mode: The case our server is not available, visitors can still access your website because CloudFlare will serve Visitors pages from your cache. Among other advantages.