Re: [Asrg] [ASRG] SMTP pull anyone?

[Steve Atkins <steve at blighty.com>]

On Aug 26, 2009, at 2:22 PM, Daniel Feenberg wrote:

> On Wed, 26 Aug 2009, John Levine wrote:
>
> > > Rich, does ipv6 change any of this?
> >
> > I'm not Rich, but the open question at this point is how effective
> > DNSBLs will be on IPv6.
>
> I think it unlikely that an IPv6 only MTA will ever have acceptance  
> even as wide as, for instance, MTAs with "pool" or "dial-up" in  
> their RDNS. IPv6 only MTAs will be refused by many MTAs. There are  
> simply too many IPv6 addresses to blacklist bad hats, and  
> blacklisting /48s would be a very broad brush. The advantage of IPv4  
> is that the number of addresses is finite, and legitimate holders of  
> addresses are loath to waste them.

I see this asserted a lot, but I don't really see much in the way of  
plausible arguments to back it up.

If anything, some blacklist techniques are likely to be easier and  
more effective on IPv6 than v4 for the obvious NAT / dynamic  
assignment reasons.

Cheers,
  Steve