I have set up a FC5 postfix mail server using the guide "Virtual Users And Domains With Postfix, Courier And MySQL (Fedora Core 5)" I want to set up a secondary mail server using a MySQL database replicated from my primary mail server. I have two boxes; mail01 and mail02 (for the sake of arguement). MySQL is replicating properly between both, so all updates to email addresses, domains, forwards (etc..etc..) are happening on mail02 (this is where some websites are stored, along with a basic web based control pannel we have written) and syncing to mail01 which is my primary mail server - this works great because the queries from postfix are read only. My intention is to make mail02 the backup MX server in the event mail01 is down. I am wanting the backup MX on mail02 to query the MySQL database to identify the domains / email addresses for which it can relay email - this would be the domains table used in the article (I assume). The result would be that when we have created new email addresses or aliases via our control pannel, it would automagically update (via MySQL replication) both the primary and secondary mail servers with the changes - this MUST be a good thing! Any help would be appreciated.