* [http://www.openldap.org/ OpenLDAP], an open source implementation of the Lightweight Directory Access Protocol.
* [http://arthurdejong.org/nss-pam-ldapd/ nss-pam-ldapd], a Name Service Switch (NSS) module that allows your LDAP server to provide user account, group, host name, alias, netgroup, and basically any other information that you would normally get from /etc flat files or NIS.
* [http://wiki.gentoo.org/wiki/Centralized_authentication_using_OpenLDAP Centralized authentication using OpenLDAP].
* [https://code.google.com/p/openssh-lpk/source/browse/trunk/schemas/openssh-lpk_openldap.schema openssh-lpk_openldap.schema] OpenSSH LDAP Public Keys.
* [http://sourceforge.net/projects/linuxquota/ linuxquota] Linux DiskQuota.