pwcheck_method: auxprop
auxprop_plugin: sql
sql_engine: mysql # or pgsql, sqlite
mech_list: plain login cram-md5 digest-md5
sql_hostnames: localhost
sql_user: sql_user
sql_passwd: sql_pass
sql_database: sql_db
sql_verbose: yes
sql_select: SELECT passwd FROM users WHERE login='%u@%r'