On 1/2/17 8:16 AM, Per Thorsheim wrote:
If using IP addresses in SPF records, is it necessary to specify both
IPv4 & IPv6 addresses? Is there currently a risk of unwanted problems if
only IPv4 (or only IPv6) addresses are specified, when a mailserver is
available using both 4 & 6?
Your SPF record will need to list all possible sending sources of email
from your domain, or it will fail the SPF test.
If you list just the IPv4 address, and the receiver gets the email from
the IPv6 address, why do you think it should pass SPF? There is no
definitive mapping to let the receiver know that IPv6 address is 'the
same' as the listed IPv4 address.
--
Richard Damon
