How to wish you hadn't forced ipv6 adoption (was "How to force rapid ipv6 adoption")
marka at isc.org
Fri Oct 2 04:18:58 UTC 2015
In message <560E00D4.7090400 at invaluement.com>, Rob McEwen writes:
> On 10/1/2015 11:44 PM, Mark Andrews wrote:
> > IPv6 really isn't much different to IPv4. You use sites /48's
> > rather than addresses /32's (which are effectively sites). ISP's
> > still need to justify their address space allocations to RIR's so
> > their isn't infinite numbers of sites that a spammer can get.
> A /48 can be subdivided into 65K subnets. That is 65 *THOUSAND*... not
> the 256 IPs that one gets with an IPv4 /24 block. So if a somewhat legit
> hoster assigns various /64s to DIFFERENT customers of theirs... that is
> a lot of collateral damage that would be caused by listing at the /48
> level, should just one customer be a bad-apple spammer, or just one
> legit customer have a compromised system one day.
A hoster can get /48's for each customer. Each customer is technically
a seperate site. It's this stupid desire to over conserve IPv6
addresses that causes this not IPv6.
> Conversely, if a more blackhat ESP did this, but it was unclear that
> this was a blackhat sender until much later.. then LOTS of spam would
> get a "free pass" as individual /64s were blacklisted AFTER-THE-FACT,
> with the spammy ESP still having LOTS of /64s to spare.. remember, they
> started with 65 THOUSAND /64 blocks for that one /48 allocation (Sure,
> it would eventually become clear that the whole /48 should be blacklisted).
> other gray-hat situations between these two extremes can be even more
> frustrating because you then have the same "free passes" that the
> blackhat ESP gets... but you can't list the whole /48 without too much
> collateral damage.
> SUMMARY: So even if you moved into blocking at the /64 level, the
> spammers have STILL gained an order of magnitudes advantage over the
> IPv4 world.... any way you slice it. And blocking at the /48 level WOULD
> cause too much collateral damage if don't indiscriminately.
> And this is assuming that individual IPs are NEVER assigned individually
> (or in smaller-than-/64-allocations) . (maybe that is a safe assumption?
> I don't know? regardless, even if that were a safe assumption, the
> spammers STILL have gained a massive advantage)
> Rob McEwen
> +1 478-475-9032
Mark Andrews, ISC
1 Seymour St., Dundas Valley, NSW 2117, Australia
PHONE: +61 2 9871 4742 INTERNET: marka at isc.org
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