How to Set Up Centralized Authentication with LDAP

LDAP (Lightweight Directory Access Protocol) provides centralized authentication and authorization. Instead of managing user accounts on every server individually, users authenticate against a central LDAP directory. This guide covers setting up OpenLDAP on your VPS.

When to Use LDAP

• Managing more than 5 servers with shared user accounts
• Need centralized password policies and account management
• Applications that support LDAP authentication (GitLab, Grafana, etc.)
• Compliance requirements for centralized access control

Installing OpenLDAP Server

# Install OpenLDAP on Ubuntu/Debian
sudo apt install slapd ldap-utils

# Reconfigure with your domain
sudo dpkg-reconfigure slapd
# DNS domain name: example.com
# Organization name: Example Inc
# Administrator password: (set a strong password)
# Database backend: MDB
# Remove database on purge: No
# Move old database: Yes

Basic LDAP Structure

# LDAP uses a hierarchical tree structure:
# dc=example,dc=com
#   ou=People          (user accounts)
#     uid=jsmith
#     uid=jdoe
#   ou=Groups          (groups)
#     cn=developers
#     cn=sysadmins

# Create the organizational units
cat > base.ldif  user.ldif  tls.ldif