De acordo com a man page ldap_table (5), as possibilidades são:
%% This is replaced by a literal ’%’ character. (Postfix 2.2 and later).
%s This is replaced by the input key. RFC 2254 quoting is used to make sure that the input key
does not add unexpected metacharacters.
%u When the input key is an address of the form user@domain, %u is replaced by the (RFC 2254)
quoted local part of the address. Otherwise, %u is replaced by the entire search string. If
the localpart is empty, the search is suppressed and returns no results.
%d When the input key is an address of the form user@domain, %d is replaced by the (RFC 2254)
quoted domain part of the address. Otherwise, the search is suppressed and returns no results.
%[SUD] The upper-case equivalents of the above expansions behave in the query_filter parameter identi‐
cally to their lower-case counter-parts. With the result_format parameter (previously called
result_filter see the COMPATIBILITY section and below), they expand to the corresponding compo‐
nents of input key rather than the result value.
The above %S, %U and %D expansions are available with Postfix 2.2 and later.
%[1-9] The patterns %1, %2, ... %9 are replaced by the corresponding most significant component of the
input key’s domain. If the input key is [email protected], then %1 is com, %2 is example and
%3 is mail. If the input key is unqualified or does not have enough domain components to satisfy
all the specified patterns, the search is suppressed and returns no results.
The above %1, ..., %9 expansions are available with Postfix 2.2 and later.