OpenLDAP, LDAP & Directory services are an enormous topic. Configuration is therefore complex. This page is a starting point for a basic openldap install on Archlinux and a sanity check.
For the newbies
If you are totally new to those concepts, here is an good introduction that is easy to understand and that will get you started, even if you are new to everything LDAP.
This part is easy:
pacman -S openldap
The openldap package basically contains two things: The LDAP server (slapd) and the LDAP client. You will probably want to run the server on your computer. After you design the directory, the server will be able to provide authentication services for LDAP clients. It is quite likely that you will run services requiring the LDAP authentication on that very computer, in which case the LDAP client will query the LDAP server from the same package.
The server (slapd)
First prepare the database directory. You will need to copy the default config file and set the proper ownership.
WARNING!!! - The following snippet wipes out any existing ldap database.
rm -rf /var/lib/openldap/openldap-data/* cp /etc/openldap/DB_CONFIG.example /var/lib/openldap/openldap-data/DB_CONFIG chown ldap:ldap /var/lib/openldap/openldap-data/DB_CONFIG
Next we prepare slapd.conf
Add some typically used schemas...
include /etc/openldap/schema/cosine.schema include /etc/openldap/schema/nis.schema include /etc/openldap/schema/inetorgperson.schema
Edit the suffix. Typically this is your domain name but it does not have to be. It depends on how you use your directory. We will use 'example' for the domain name, and 'com' for the tld. Also set your ldap administrators name (we'll use 'root' here)
suffix "dc=example,dc=com" rootdn "cn=root,dc=example,dc=com"
Now we delete the default root password and create a strong one:
#find the line with rootpw and delete it sed -i "/rootpw/ d" slapd.conf #add a line which includes the hashed password output from slappasswd echo "rootpw $(slappasswd)" >> slapd.conf
ldap won't find things unless you index them. Read the ldap documentation for details, you can use the following to start with. (add them to your
index uid pres,eq index mail pres,sub,eq index cn pres,sub,eq index sn pres,sub,eq index dc eq
Don't forget to run
slapindex after you populate your directory. (slapd needs to be stopped to do this). Then change the ownership for all the generated files:
chown ldap.ldap /var/lib/openldap/openldap-data/*
If you want to use SSL, you have to specify a path to your certificates here. See OpenLDAP Authentication
Finally you can start the slapd daemon.
#systemctl start slapd
It might be possible that /run/openldap does not exist, starting the daemon won't work. Just create the directory:
- mkdir /run/openldap
Very important, you define here on which port the server should listen and if you want to use SSL, you will want to use the ldaps:// URI instead of the default ldap:// You can also specify additional slapd options here.
The client is usually not such a big deal, just keep in mind that your apps that require LDAP auth use it, so if something goes wrong with LDAP, do not waste your time with the app, start debugging the client instead.
The client config file is located at /etc/openldap/ldap.conf It is actually very simple.
If you decide to use SSL:
- The protocol (ldap or ldaps) in the URI entry has to conform with the slapd configuration
- If you decide to use self-signed certificates, you have to add them to TLS_CACERT
Test your new OpenLDAP installation
This is easy, just run the command below:
ldapsearch -x -b -s base '(objectclass=*)' namingContexts
you should see some information on your database.
You now have a basic ldap installation. The step is to design your directory. The design is heavily dependent on what you are using it for. If you are new to ldap, consider starting with a directory design recommended by the specific client services that will use the directory (PAM, Postfix, etc).
A directory for system authentication is the LDAP Authentication article.
If you notice that slapd seems to start but then stops, you may have a permission issue with the ldap datadir. Try running:
# chown ldap:ldap /var/lib/openldap/openldap-data/*
to allow slapd write access to its data directory as the user "ldap"