>
> reject_unknown_client_hostname (with Postfix < 2.3:
> reject_unknown_client)Reject the request when 1) the client IP
> address->name mapping fails, 2) the name->address mapping fails, or 3)
> the name->address mapping does not match the client IP address.
> This is a stronger restriction than
>>
>
> If you are using Postfix, the following smtpd_recipient_restrictions work
> well for us. Note that you need to install policy-spf-python before you can
> use the last directive.:
>
> smtpd_recipient_restrictions = permit_mynetworks, reject_unauth_destination,
> reject_invalid_hostname, re
