On 12/04/2022 01:12, Andy Smith wrote:
[snip]
> Note that it is not really important that the reverse and forward
> DNS records match anything that is in the email headers, just that
> they match *each other* (reverse DNS resolves to a host name that
> also resolves back to the same IP address).
This used to be the case but I hit a problem the other day of an ISP who
insisted not only that they matched each other but that they also
matched the name given in the HELO part of the SMTP dialogue.
This was a new requirement from that ISP which caused email to bounce.
A nuisance when you have several logical mail servers behind a single
IPv4 address.
So much easier with ISPs who are up to date and use IPv6.
John
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