Since filtering needs to be done as close to the source as ...

[dbose]

Since filtering needs to be done as close to the source as possible by routers or gateways knowing the valid address ranges of incoming packets,
 
  an _______ is best placed to ensure that valid source addresses are used in all packets from its customers.
  What will be an ideal response?

Question 2

The four lines of defense against DDoS attacks are: attack prevention and preemption, attack detection and filtering, attack source traceback and identification and _______.
 
  What will be an ideal response?

[aadams68]

Answer to Question 1

ISP

Answer to Question 2

attack reaction

[dbose]

YES! Correct, THANKS for helping me on my review

[nanny]

Thanks for the timely response, appreciate it