Re: DNSBL and IPv6

On Fri, 19 Oct 2012, Matthias Leisi wrote:

> On Fri, Oct 19, 2012 at 8:22 AM, Mikael Abrahamsson <[email protected]> wrote:
>
>> Fundamentally in IPv6, a "customer" (or entity or whatever) will in a lot of
>> cases not a single IP address, but a network.
>
> At the beginning of an SMTP transaction, all you have is a single IP.

Yes.

>> Households will get /64s, or get a /56 via DHCPv6-PD. Phones get a /64 or a
>> network via DHCPv6-PD. Companies get /48 (or something else, but a bunch of
>
> As a spam filter (software developer), you may want to know more about
> the reputation of the IP address connecting to you.

Yes, and that reputation is derived from what subnet it's a subset of.

> You need an algorithm where you start from a single IP address and then 
> potentially "move up" until you get a meaningful result. That's more or 
> less what the B-tree algorithm suggested by John Levine some months ago 
> would offer: variable "depth" and "density" of data controlled by the 
> DNSxL operator optimized for the (on average) lowest number of lookups 
> needed.

Sounds good to me.

> At the same time, having a standardised and light-weight protocol to
> determine the allocation policy by the ISP would be hugely helpful
> (this will likely then be mirrored by the DNSxL operator). Absent such
> data,third parties have to fall back to some default /64 etc.

Yes, which will be less than effective when customers are handed /48s and 
can send from anything within that /48.

>> What I feel needs to happen is that policy needs to put in place to 
>> RIRs (via ISPs) can present "what is a customer" on a network level, 
>> and then this information can be put into DNS somehow, and used for 
>> DNSBL.
>
> I don't know whether RIRs can mandate the publication of this data
> through policy.

RIPE already does (basically), as in "this /42 contains customers where 
each customer has a /56". I don't know about other RIRs.

-- 
Mikael Abrahamsson    email: [email protected]