If I've not opened the port 80, how can someone DDoS me?

Is there a method or is it possible?

Someone said that it's possible, but I'm not so sure, that's why I'm asking here.

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    why do you think that port 80 is involved in DDoS? – schroeder Oct 2 '15 at 22:23
  • So someone can attack me? – James Dake Oct 2 '15 at 22:25
  • I'm asking what connection you made between port 80 and DDoS. – schroeder Oct 2 '15 at 22:35
  • @JamesDake, any port can be blocked. If you're worried about protection it may help to set something to a nonstandard port, though this is only minimal obscurification – Steven Walton Oct 3 '15 at 0:19
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    You might find it helpful to read this question and answer: How do DoS attacks work on non-servers? – CBHacking Oct 5 '15 at 22:23

I think your confusion comes from not quite understanding exactly what comrpises a DDoS attack.

DDoS means Distributed Denial Of Service

Let's take off "Distributed" for now, and break down what this means.

Denial Of Service. Rendering something unusable is about the best way to say this in a generic, non-computer or technology specific way. That family of slow, ignorant people who walk side-by-side in the mall and block everyone? They are, essentially, a Denial of Service attack on their fellow mall dwellers. They make it hard or impossible to walk swiftly down the hallway in the mall.

If I write a script that constantly tries to brute force guess the login credentials to your SSH server, and it sends so much traffic that neither you nor anyone else can get a prompt from the server to try THEIR credentials, then I am denying you and them access to the SSH server, aka Denying access to the Service.

It has nothing implicitly to do with tcp/80. That's just a popular port to attack because Internetz.

A bunch of hippies standing, locked arms, around a government building, making it so someone can't easily cross their line and enter the building? That is also a denial of service.

However, these are all cases of denying OVERT or ACTIVE services. Consider the old-school Ping of Death. A ping packet that has no end (or at least, is bigger than the RFC spec), is a Denial of Service if your system is too old to know how to respond and thus crashes. Your system is down, and I have denied you the use of it. DOS.

If I throw so much traffic at your IP that your router/nic/modem can't reject or drop it fast enough, I am DOSing your system.

Now the ONLY difference with a DISTRIBUTED DOS is the source of the attack. Distributed implies multiple sources are attacking the same target(s) in a somewhat coordinated manner.

If you DOS me from your home IP, I call up The Internet Police (lol) and tell them to block your traffic upstream from me. Problem solved. With a DDoS, they have to block traffic from MANY sources. And an effective DDoS keeps changing sources.

Hope that helps!

  • 1
    Most DoS attacks against residential internet connections are bandwidth-exhaustion attacks that saturate the connection instead of overloading the modem/router. – André Borie Oct 3 '15 at 6:25

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