Re: [exim] exim4, gmail and 550-5.7.1

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Author: John C Klensin
Date:  
To: Jeremy Harris, exim-users
Subject: Re: [exim] exim4, gmail and 550-5.7.1


--On Saturday, December 12, 2015 13:49 +0000 Jeremy Harris
<jgh@???> wrote:

> On 11/12/15 21:22, Robert Steinmetz AIA wrote:
>> Any email to a gmail server is rejected with a 550-5.7.1
>> error, basically requiring a ipv6 ptr record.
> [...]
>> Unfortunately our IP addresses are provided by our ISPs and
>> they don't provide ipv6 ptr records.
>
> That's your basic problem; go beat up your ISP or move to a
> better one - because, big-G will proceed in the future to
> apply the same constraints to ipv4. My prediction; I have no
> special knowledge. But "we're the phone company; we don't
> have to care".


Additional suggestion, since the RIRs have repeatedly claimed to
be responsive to public input, not just the needs and desires of
their largest ISP members: complain to your RIR and try to get
them to adopt a requirement that providing reverse-mapping
records of some plausible sort (for both IPv4 and IPv6) is a
condition for [continued] allocation of address space to ISPs
who will then further allocate or assign it as
provider-dependent space.

Such a policy would provide far stronger incentives to your (and
other) ISPs than any amount of beating up you are likely to be
able to do directly. Unless the RIRs and IETF/IAB want to band
together and denounce the availability of reverse-mapping
records as a validity test (something I certainly would not
advocate), the willingness to support such records should not be
an opportunity for competition among ISPs.

    john