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HowTo/LDAP

LDAP Overview

This guide is meant to provide general guidance on configuring an LDAP client to connect to IPA. There are specific guides/Howtos for some clients/servers.

Data layout (DIT)

The basedn in an IPA installation consists of a set of domain components (dc) for the initial domain that IPA was configured with. If you installed IPA with the domain example.com then your basedn is dc=example,dc=com. We often refer to this as $SUFFIX. Don't confuse this with DNS domains. You will only ever have one basedn, the one defined during installation.

You can find your basedn, and other interesting things, in /etc/ipa/default.conf

IPA uses a flat structure, storing like objects in what we call containers. Some container examples are:

  • Users: cn=users,cn=accounts,$SUFFIX
  • Groups: cn=groups,cn=accounts,$SUFFIX

System Accounts

There are some LDAP clients that need a pre-configured account. Some examples are the LDAP autofs client and sudo. Using a user's credentials is generally preferable to creating a shared system account but that is not always possible. Do not use the Directory Manager account to authenticate remote services to the IPA LDAP server. Use a system account, created like this:.

# ldapmodify -x -D 'cn=Directory Manager' -W
dn: uid=system,cn=sysaccounts,cn=etc,dc=example,dc=com
changetype: add
objectclass: account
objectclass: simplesecurityobject
uid: system
userPassword: secret123
passwordExpirationTime: 20380119031407Z
nsIdleTimeout: 0
<blank line>
^D

Be sure to change the password to something more secure, and the uid to something reasonable.

The reason to use an account like this rather than creating a normal user account in IPA and using that is that the system account exists only for binding to LDAP. It is not a real POSIX user, can't log into any systems and doesn't own any files.

This use also has no special rights and is unable to write any data in the IPA LDAP server, only read.

Note: IPA 4.0 is going to change the default stance on data from nearly everything is readable to nothing is readable, by default. You will eventually need to add some Access Control Instructions (ACI's) to grant read access to the parts of the LDAP tree you will need.

SSL/startTLS

When possible, configure your LDAP client to communicate over SSL/TLS. You can either use port 389 and enable startTLS in the client or configure to use the ldaps port, 636. The IPA CA certificate can be found in /etc/ipa/ca.crt on all enrolled hosts.

Tool configuration

Since IPA 3.0 we've configured /etc/openldap/ldap.conf with some bare defaults:

URI ldaps://ipaserver.example.com
BASE dc=example,dc=com
TLS_CACERT /etc/ipa/ca.crt

Setting these defaults means you don't need to pass as many options to tools like ldapsearch.

So you can do this:

$ ldapsearch -x uid=admin

Rather than:

$ ldapsearch -x -h ipa.example.com  -b dc=example,dc=com uid=admin

Unix clients

For specific information on configuring Unix clients to authenticate against IPA, see ConfiguringUnixClients

As a general rule, we recommend using RFC 2307bis when possible. If this is not possible, we provide a compatibility layer that provides the same information in an RFC 2307-compatible way. The only change you need to make is to set the basedn to cn=compat,$SUFFIX