Directory Proxy Server works with Directory Server to ensure reliability and to protect against denial-of-service attacks. Directory Proxy Server automatically routes requests appropriately and provides secure firewall-like services for Directory Server.
To prevent a single point of failure for mission-critical applications, Directory Proxy Server detects outages and routes traffic around affected areas, effectively load balancing requests across systems. When the affected areas are restored to operation, Directory Proxy Server detects the restored servers automatically.
For more information, see Using Directory Proxy Server as Part of a Redundant Solution.