I had first created a new user, emailcatchall, and as with most new accounts I set the shell to be /sbin/nologin. I also added a always_bcc to main.cf expecting this to work. When it didn't, I tried adding a cc "!emailcatchall" to the start of maildroprc but this didn't work either. Both ways lead to no mail being delivered by maildrop with an error talking about the filter file. In my efforts to trouble shoot the problem, I eventually gave the account a /bin/sh shell and 'boom', it all worked.

So, my question is: Is this normal?

My concern is that I won't be able to assign my users (all are real unix users) with a /sbin/nologin or a /bin/ftponly shell and still have them receive email. I'm sure this shouldn't be the case so how do I enable users to receive emails yet restrict their ability to log into the server using ssh or ftp? The first part of the postfix-maildrop howto is for virtual users but in my case they are real accounts. By not giving them shell rights, does that make them 'virtual' to maildrop and I have to do something differently?