Question about DDoS...

Question

Hey,

I am learning about DDoS attacks and all that kind of stuff, so I've started to gain more questions then answers.This is about UDP TCP layer.

1. Why closed port cannot be attacked?
2. Why filtered port is better then closed?
3. Why is it better to have filtred ports?
4. If the server usses 22005 port for connections, is there need to filter other ports or is it fine if they are not filtered?

Answer 1

1. Closed ports are not listening for connections, and will not accept any packets destined to them.
2. Filtering port numbers is useful for security reasons. Each open port is a potential avenue for an attacker. Keeping ports down to the bare minimum keeps you from exposing yourself to further vectors of attack
3. Same as #2
4. Not sure I follow this question. In general, we follow the principle of least privilege. The fewer open ports on a host, the better.