* Zachary Uram sez: : so then firewall totally helpless to DoS attack? Sure, your problem will be (in a flood based DoS attack) line-saturation and CPU spikes on your Layer-X devices. The firewall won't help you much in de-saturating the network in front of her. : such as all packets are encrypted to u and are ignored by default Still, someone has to inspect those packets and they have to arrive there.