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Re: Source address validation (was Re: UUNet Offer New ProtectionAgainst DDoS)
--On 06 March 2004 18:39 -0500 Sean Donelan <firstname.lastname@example.org> wrote:
Source address validation (or Cisco's term uRPF) is perhaps more widely deployed than people realize. Its not 100%, but what's interesting is despite its use, it appears to have had very little impact on DDOS or lots of other bad things.
But relatively few DDOS attacks use spoofed packets. If more did, they would be easier to deal with.
AIUI that's cause & effect: the gradual implementation of source-address validation has made attacks dependent on spoofing less attractive to perpetrators. Whereas the available of large pools of zombie machines has made the use of source spoofing unnecessary. Cisco et al have shut one door, but another one (some suggest labeled Microsoft) has opened. Those with long memories might draw parallels with the evolution of phreaking from abuse of the core, which became (reasonably) protected to abuse of unprotected PABXen. As I think I said only a couple of days ago, there is nothing new in the world. Alex