I have redirection aliases set up using virtual domain accounts, all specified using webadmin and in /etc/courier/aliases/webadmin with entries such as

@frobniz.com: vmail-frobniz

The vmail user account holds all virtual domain accounts as well as being the home directory for all hosted domains, and redirection is done in ~vmail with files such as .courier-frobniz-default. Global maildrop recipient policies for embedded maildrop are in ~vmail/.mailfilters/rcptfilter-alias-default, which works.

How do I set up a per-alias rcptfilter file for a single alias, say frobniz (and yes, frobniz.com is registered working domain :-). I've tried putting the instructions in:

~vmail/.mailfilters/rcptfilter-frobniz-default ~vmail/.mailfilters/rcptfilter-alias-frobniz-default ~vmail/.mailfilters/rcptfilter-frobniz ~vmail/.mailfilters/rcptfilter-alias-frobniz

None of these work. What extensions should I use with the rcptfilter filename to make it specific to a single alias?