The OpenVPN Auth-LDAP Plugin implements username/password authentication
via LDAP for OpenVPN 2.x.

Features
- User authentication against LDAP.
- Simple Apache-style configuration file.
- LDAP group-based access restrictions.
- Integration with the OpenBSD packet filter, supporting adding and
removing VPN clients from PF tables based on group membership.
- Tested against OpenLDAP, the plugin will authenticate against any
LDAP server that supports LDAP simple binds -- including Active
Directory.