Question about dynamic IPv6-PTR-Generation

sthaug at sthaug at
Sat Aug 27 08:28:22 UTC 2016

> > >A very popular option is to only create or delegate IPv6 PTR entries
> > >for hosts with static address assignments, and to return NXDOMAIN for
> > >address space used for dynamic address assignments.
> >
> > I talk to a lot of large providers at M3AAWG and that's the consensus
> > about what to do.  If it doesn't have a static address, it's not a
> > server and it doesn't need rDNS.
> Simply pretending a shark doesn't exist offers very little in shark
> protection.  While I understand this school of thought I don't believe
> it will solve the problem or remove the need.

We're still in the early phases of IPv6. If sufficient ISPs drop PTR
for dynamic IPv6 addresses, email providers and others who base some
sort of "reputation" on IPv4 PTRs today will simply have to adapt.

Steinar Haug, Nethelp consulting, sthaug at

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