Alias_filter alias option
alias_filter alias option is the analogue of the legacy configuration [FILTER] alias file named parameter. It takes a URL argument specifying the location of a Sieve filter to apply on attempted message postings. The argument may be any supported form of URL that makes sense; in particular, besides supporting
file:file-spec URLs or simply file specifications without the leading
file:, LDAP URLs, and
data:sieve-commands are also supported. Note that when specifying a file, it must be the full file specification for the filter file to apply.