Overall this is a really hard problem....
There are, from memory, several things that you might wish to use to
allow/reject messages:-
- TSL settings, including TLS certificates
- IP addresses, networks/netmasks of connecting host
- host/domainname of connecting host
- DNS registration or not (+allow_unknown)
- RBL information
- SMTP authentication
- sender envelope address
- recipient envelope address (ie allow mail to postmaster)
How on earth we can extend the configuration to sanely allow any
combination of these without coming up with a scheme thats harder to
read and understand than a sendmail.cf file is rather difficult :-(
Nigel.
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[ Nigel Metheringham Nigel.Metheringham@??? ]
[ Phone: +44 1423 850000 Fax +44 1423 858866 ]