nanog mailing list archives
Re: Using IPv6 with prefixes shorter than a /64 on a LAN
From: Matthew Petach <mpetach () netflight com>
Date: Sun, 30 Jan 2011 15:17:19 -0800
On Tue, Jan 25, 2011 at 10:26 PM, Fernando Gont <fernando () gont com ar> wrote:
On 24/01/2011 07:41 p.m., Michael Loftis wrote:Many cite concerns of potential DoS attacks by doing sweeps of IPv6 networks. I don't think this will be a common or wide-spread problem. The general feeling is that there is simply too much address space for it to be done in any reasonable amount of time, and there is almost nothing to be gained from it.The problem I see is the opening of a new, simple, DoS/DDoS scenario. By repetitively sweeping a targets /64 you can cause EVERYTHING in that /64 to stop working by overflowing the ND/ND cache, depending on the specific ND cache implementation and how big it is/etc.That depends on the ND implementation being broken enough by not limiting the number of neighbor cache entries that are in the INCOMPLETE state. (I'm not saying those broken implementations don't exist, though).
Even without completely overflowing the ND cache, informal lab testing shows that a single laptop on a well-connected network link can send sufficient packets at a very-large-scale backbone router's connected /64 subnet to keep the router CPU at 90%, sustained, for as long as you'd like. So, while it's not a direct denial of service (the network keeps functioning, albeit under considerable pain), it's enough to impact the ability of the network to react to other dynamic loads. :/ Matt
Current thread:
- Re: Using IPv6 with prefixes shorter than a /64 on a LAN, (continued)
- Re: Using IPv6 with prefixes shorter than a /64 on a LAN Owen DeLong (Jan 26)
- Re: Using IPv6 with prefixes shorter than a /64 on a LAN Karl Auer (Jan 26)
- Re: Using IPv6 with prefixes shorter than a /64 on a LAN eric clark (Jan 31)
- Re: Using IPv6 with prefixes shorter than a /64 on a LAN Owen DeLong (Jan 31)
- Re: Using IPv6 with prefixes shorter than a /64 on a LAN Michael Dillon (Jan 31)
- Re: Using IPv6 with prefixes shorter than a /64 on a LAN Owen DeLong (Jan 31)
- Re: Using IPv6 with prefixes shorter than a /64 on a LAN Owen DeLong (Jan 25)
- Re: Using IPv6 with prefixes shorter than a /64 on a LAN Ray Soucy (Jan 26)
- RE: Using IPv6 with prefixes shorter than a /64 on a LAN George Bonser (Jan 25)
- Re: Using IPv6 with prefixes shorter than a /64 on a LAN Fernando Gont (Jan 25)
- Re: Using IPv6 with prefixes shorter than a /64 on a LAN Matthew Petach (Jan 30)
- Re: Using IPv6 with prefixes shorter than a /64 on a LAN Fernando Gont (Jan 30)
- Re: Using IPv6 with prefixes shorter than a /64 on a LAN Matthew Petach (Jan 31)
- Re: Using IPv6 with prefixes shorter than a /64 on a LAN Mikael Abrahamsson (Jan 30)
- Re: Using IPv6 with prefixes shorter than a /64 on a LAN Per Carlson (Jan 31)
- Re: Using IPv6 with prefixes shorter than a /64 on a LAN Mikael Abrahamsson (Jan 31)
- Re: Using IPv6 with prefixes shorter than a /64 on a LAN Mark Andrews (Jan 24)
- Re: Using IPv6 with prefixes shorter than a /64 on a LAN Owen DeLong (Jan 24)
- Re: Using IPv6 with prefixes shorter than a /64 on a LAN sthaug (Jan 24)
- Re: Using IPv6 with prefixes shorter than a /64 on a LAN Mark Smith (Jan 25)