I have a couple of mail servers that act only as SMTP relay, and SMTP backup servers.
How can I reject invalid recipient addresses at these servers? I have investigated the manual on local_recipient_maps, however it appears that this is only useful for email where the machine involved is the final destination. In this case these 2 machines operate in a load-balanced manner, forwarding email onto the final server, or in a few instances acting as an MX20 backup. I can make available to these servers (via SQL replication) a list of 'valid' email addresses from the destination mail server(s), how can the valid/invalid address accept/deny be deployed?
