Hi,
Our customer has a large number of servers allowed in the HAT in the RELAY LIST group. So basically every server is able to send email out!! We know it is bad
We would like to filter outgoing email, based on the sender email address. Restricting with based on IP source is not possible at the moment since the customer has not an overal view of the servers
The idea is: "Only valid email sender can send email"
Is it possible to do so? Maybe with an LDAP group? Because I don't think we have the equivalent of the LDAP "Accept Query" to allow sender.
What would be the impact in term of performance?
By definition we don't know what are the outgoing email addresses, maybe the idea is to block all email addresses that are not in the LDAP server.
Or any other idea...
Thanks for th help or idea