Effective ways to deal with DDoS attacks?

Thu May 2 13:57:52 UTC 2002

On Thu, 2 May 2002, Avleen Vig wrote:

> > Basically, it works like this: when you identify the target of the attack,
> > you have traffic for those target addresses rerouted to a "filter box".
> > This filter box then contains source address based filters to get rid of
> > the attacking traffic.

> Two questions:
>   1) How do you plan on determining what an allowed src address and what
>      isn't?

"allowed"?

>   2) Secondly, how would you deal with spoofed src addresses where the src
>      address is rarely repeated in the attack?

If that is the case, this solution won't help. Unfortunately, it is
impossilbe to prevent traffic with spoofed source addresses to come in
over transit connections. However, it is doable to make sure traffic
coming in from peers uses source addresses that belong to peers. So for
networks large enough to have a major part of their traffic coming in over
peering rather than transit, there are possibilities.