Creating example LDAP server via OpenLDAP

Here is the guidline to create a LDAP server for testing purpose:

If you're using Public Cloud providers, might be better idea to use Private IP address:

#for example:
{
    PRIVATE_IP=10.0.1.6
    LDAP_FQDN=ldap-server.example.local
    echo "$PRIVATE_IP $LDAP_FQDN" >> /etc/hosts
}

Install OpenLDAP package:

Here in this steps, it will prompt you for configuring LDAP administrator password.

{
    apt update
    apt install slapd ldap-utils
}

Now and after installation has finished, we need to configure LDAP server:

dpkg-reconfigure slapd

Make sure to click No and proceed.

At the next step we need to configure a DNS name for the LDAP base DN:

In our example it would be example.local

And also it's same for the next step as Organization

after providing the administrator password, select No when it prompted for purging the db:

And finally select Yes for moving the old DB:

Configuring OpenLDAP config file:

Now it's time to reconfigure LDAP config file to use the new information we just configured:

{
    vi /etc/ldap/ldap.conf
}

#Uncomment and provide the correct info:

BASE dc=example,dc=local

URI ldap://ldap-server.example.local

{
    systemctl restart slapd
    systemctl status slapd
}

You can check and verfy the LDAP configuration by this command:

{
    ldapsearch -Q -LLL -Y EXTERNAL -H ldapi:///
}

Activate `memberOf'

First we need to check current module list to check then next index we should create a new entry with the next available index for memberOf module:

ldapsearch -Q -LLL -Y EXTERNAL -H ldapi:/// -b cn=config '(objectClass=olcModuleList)' dn

# or 

ls  /etc/ldap/slapd.d/cn\=config/

In our example the next available index is 1:

cat > load-memberof.ldif
dn: cn=module{1},cn=config
objectClass: olcModuleList
cn: module{1}
olcModulePath: /usr/lib/ldap
olcModuleLoad: memberof.la

ldapadd -Q -Y EXTERNAL -H ldapi:/// -f load-memberof.ldif
adding new entry "cn=module{1},cn=config"

#Verify module list:

ldapsearch -Q -LLL -Y EXTERNAL -H ldapi:/// -b cn=config '(objectClass=olcModuleList)' dn
dn: cn=module{0},cn=config

dn: cn=module{1},cn=config

#To determine which database configuration you need to apply the memberOf overlay to, you can perform an LDAP search to list the database entries in your configuration:

ldapsearch -Q -LLL -Y EXTERNAL -H ldapi:/// -b cn=config '(objectClass=olcDatabaseConfig)' dn
dn: olcDatabase={-1}frontend,cn=config

dn: olcDatabase={0}config,cn=config

dn: olcDatabase={1}mdb,cn=config

#Configure the memberOf overlay

cat > memberof-overlay.ldif 
dn: olcOverlay=memberof,olcDatabase={1}mdb,cn=config
objectClass: olcOverlayConfig
objectClass: olcMemberOf
olcOverlay: memberof
olcMemberOfDangling: ignore
olcMemberOfRefInt: TRUE

ldapadd -Q -Y EXTERNAL -H ldapi:/// -f memberof-overlay.ldif
adding new entry "olcOverlay=memberof,olcDatabase={1}mdb,cn=config"

#restart the slapd

systemctl restart slapd

#Verify memberOf module:

ldapsearch -Q -LLL -Y EXTERNAL -H ldapi:/// -b cn=config olcOverlay=memberof
dn: olcOverlay={0}memberof,olcDatabase={1}mdb,cn=config
objectClass: olcOverlayConfig
objectClass: olcMemberOfConfig
olcOverlay: {0}memberof
olcMemberOfDangling: ignore
olcMemberOfRefInt: TRUE

Creating two main OUs for storing other groups and users:

Run below command to add OUs to the LDAP:

ldapadd -x -D cn=admin,dc=example,dc=local -W -f organizationalUnits.ldif

Creating some random groups for storing users:

Run below command to add groups to the LDAP:

ldapadd -x -D cn=admin,dc=example,dc=local -W -f groups.ldif

Creating some random users:

First we need to generate a password for users, so you can run this command to generate a new one and replace the while encrypted result with password userPassword in users.ldif file.

slappasswd

Next, run below command to add users to the LDAP:

ldapadd -x -D cn=admin,dc=example,dc=local -W -f users.ldif

Verifying all created objects.

Now you can run below commands to verify all the objects we just created:

ldapsearch -x -LLL -b "uid=Liam,ou=users,dc=example,dc=local" memberOf
dn: uid=Liam,ou=users,dc=example,dc=local

ldapsearch -x -LLL -b "uid=Olivia,ou=users,dc=example,dc=local" memberOf
dn: uid=Olivia,ou=users,dc=example,dc=local

ldapsearch -Q -LLL -Y EXTERNAL -H ldapi:///

ldapsearch -D "cn=admin,dc=example,dc=local" -W -b "OU=users,DC=example,DC=local"

ldapsearch -x -LLL -b dc=example,dc=local '(uid=Charlotte)' cn uidNumber gidNumber