On 2025-06-17 at 14:40:38 UTC-0400 (Tue, 17 Jun 2025 20:40:38 +0200)
Sebastian Nielsen via mailop <[email protected]>
is rumored to have said:
Its not uncommon.
Worst possible argument. The fact that a discernible number of firewalls
do this is an argument against those firewalls.
Many have that problem with firewalls automatically doing that.
I can understand that, as it is a conceptual problem in the
configuration or design of those firewalls. They are unfit for the
purpose of protecting mail systems.
It will break more than SPF. It also will break any attempt to use any
form of DNSBL. Returning loopback values in DNS has a standardized
widely-used function that demands the unimpeded receipt of loopback
answers to A and AAAA queries.
--
Bill Cole
[email protected] or [email protected]
(AKA @[email protected] and many *@billmail.scconsult.com
addresses)
Not Currently Available For Hire
_______________________________________________
mailop mailing list
[email protected]
https://list.mailop.org/listinfo/mailop
