man transport contains the same text as /etc/postfix/transport. I already read this file and virtual and generic and what else there is :-) The main point is that these work as "nexthop" destinations. But "we" do not want to "hop". We want to "hop *and* deliver here" so to speak. I do not see any option to specify a "deliver to here and also deliver to here" for these maps. The only option is something like
whatever way I do this it just delivers to one destination. What my client needs is deliver to two or more destinations, where one destination (or maybe all) cannot be changed.
The only way I see one could do this with transport is to redirect to an alias, maybe like this:
and then in aliases:
With this approach it doesn't matter what the mailuser changes and writes to .forward.
Do you think this would work? (Not sure, if it's actually local: or not virtual: that I should use here.) What do you think? DSo you see something better?
This would need the client to edit transport and aliases, but he should be able to do it in Webmin. And it avoids fiddling around with any ISPConfig stuff.