How would I deal with DDos's?

[Aeternal]

I was wondering how would I end up dealing with DDos's? (Dat grammar)
I currently host with NFO and every once in a while someone will DDos the server. NFO of course handles it but I want to know how could I get certain info? Like the type of packets that are trying to flood the server along with their IP's?
NFO 'null routes' DDos's so that they don't affect the server as much but what does it mean exactly?
(I'm assuming that they get the type of packets being sent and send them to a blank IP or something?)

[Dawnkiller]

Don't understand why you would need to know?

A null route means putting a blanket ban on a certain set of IPs by enforcing a redirect into a null IP such as 127.0.0.1 (localhost).

They don't enforce the ban on a certain "type" of packet. A null route affects ALL traffic from an IP.

[Abdul]

You could try to request IP's from NFO that their automated systems blocked during the attack.