Re: [exim] Exim ACL to Limit Incoming Server Sources

Quoting Chris Miller:

> In other words, if the user's domain is listed in +filtered_domains,
> only accept it from +filtering_servers, otherwise process normally.

in acl_check_rcpt:

defer
message = use the proper MX
domains = +filtered_domains
hosts = +filtering_servers

use deny instead of defer if you like it harder. If the server is not
listed as MX for +filtered_domains at all, deny is ok, I think.

You should also think if there are other legit senders, e.g. 127.0.0.1
or other MTAs or MUAs which you are smarthost for. If they use SMTP
AUTH, you should insert "! authenticated = *".