Send all local mail to ISP email addresses in Postfix

Question

I have a server running Postfix 2.6.5, and all of the local users have email accounts through the company ISP. These accounts have the same usernames as their usernames on the server.

I would like any locally sent email (i.e., sent to joe@local.localdomain or just joe) to be sent directly to the ISP accounts (i.e., joe@my-isp.com). I don't want the users to even have mailboxes on the server.

Using smtp_generic_maps looks close, but I think it requires a separate line for every user in the system. Do I need to put regexps in generic? Or is there an easier way to do this?

Answer 1

Use virtual delivery, as follows:

@local.localdomain @my-isp.com

See virtual(5) for more information on how this works, and why (specifically, the "RESULT ADDRESS REWRITING" section).