mod_quotatab_ldapmod_quotatab submodule is contained in the
mod_quotatab_ldap.c, and is found in the contrib/
area of the ProFTPD source distribution.  See the mod_quotatab
installation instructions.
This submodule provides the LDAP-specific "driver" for retrieving quota limit table information from an LDAP server.
Please contact John Morrissey <jwm at horde.net> with any questions, concerns, or suggestions regarding this module.
The mod_quotatab_ldap module supports the "ldap" string
for the source-type parameter of the
QuotaLimitTable
configuration directive.
To enable LDAP-provisioned limit tables, you need to configure
mod_ldap to lookup the proper attribute using the
LDAPDoQuotaLookups configuration directive.
The LDAP attribute to be looked up (named ftpQuota by default)
should contain a comma-separated list of 8 values, in the following order:
  per_session, limit_type, bytes_in_avail, bytes_out_avail, bytes_xfer_avail,
    files_in_avail, files_out_avail, files_xfer_avail
For example:
"false,hard,100,100,100,100,100,100"
An example proftpd.conf configuration might look like:
  <IfModule mod_quotatab.c>
    <IfModule mod_quotatab_ldap.c>
      # Enable LDAP quota lookups
      LDAPDoQuotaLookups on
      # Use an LDAP-based limit table.  Note that there is no additional
      # information supplied after the source-type: this is intentional. 
      # mod_ldap handles the rest.
      QuotaLimitTable ldap:
    </IfModule>
    # Use a file-based tally table
    QuotaTallyTable file:/usr/local/proftpd/ftpquota.tallytab
  </IfModule>