Thanks, Sebastian. The first block did exactly what I needed.
On Tuesday, February 5, 2019 8:48:46 AM MST Sebastian Nielsen via Exim-users
wrote:
> in acl_mail (before SPF check):
>
> accept
> authenticated = *
> sender_domains = +local_domains
> set acl_m0 = authorizedrelay
> deny
> message = You can't spoof the domains this server is authorative for
> sender_domains = +local_domains
>
>
> then in acl_data:
> deny
> message = You can't spoof the MIME From this server is authorative for
> condition = ${if match
> {$h_from:}{^(?i).*<.*@(.*YOUR_DOMAIN_HERE>\$}{yes}{no}} condition = ${if eq
> {$acl_m0}{authorizedrelay}{no}{yes}}
>
> Den tis 5 feb. 2019 kl 15:37 skrev Al T. via Exim-users <exim-
users@???>:
> > I have an interesting problem I haven't been able to solve. I keep
> > searching for a solution but I can't seem to find an answer.
> >
> > Users of my domain are required to authenticate in order to submit email.
> > Additionally, SPF is enabled and rejects all mail not originating from my
> > MX server (v=spf1 a mx -all).
> >
> > I have manually tested both of these policies and they are working as they
> > should, except in one case: if the MAIL FROM and RCPT TO address are the
> > same, the mail is accepted without requiring authentication, and without
> > validating the SPF record. This means some spam gets through by simply
> > claiming to be from me to me.
> >
> > Any ideas why Exim does that and how to block it?
> >
> > --
> > Al T.
> > alf@???
> >
> >
> >
> > --
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--
Al T.
alf@???