CiraSync On-Premise: Server and Software Requirements

To install and run CiraSync On-Premise successfully, your environment must meet the following server and software prerequisites.

Operating System:
A member server joined to your Active Directory domain running Windows Server 2019, 2022, or 2025 (either physical or virtualized).
Memory:
Minimum of 8 GB RAM.
Processor:
- At least 2 cores for deployments with fewer than 300 target mailboxes.
- At least 4 cores for environments with more than 300 mailboxes.
Storage:
Minimum of 100 GB of free hard drive space.
Network Access:
- Internet access is required.
- Port 80 must be open for both inbound and outbound traffic.
Antivirus and Network Security Notes:
- Packet Inspection Software:
  It is critical to disable any packet inspection software (e.g., Cylance, Symantec Endpoint Protection, Sophos, Cisco AMP). CiraSync relies on a high volume of EWS packets through port 443 and internal data exchange across multiple ports. Packet inspection can significantly degrade performance and prevent mailbox updates.
- Real-Time Antivirus Monitoring:
  Add an exclusion for the following directory to avoid interference with application files:
  C:\Program Files (x86)\itrezzoAgent\...

Web Services (IIS):
The CiraSync On-Prem Unified Contact Management (UCM) platform uses Internet Information Services (IIS) on Port 80.
Required roles and features must be enabled to support the Employee Contact Portal.

For setup assistance, see: Configuring Unified Contact Management on Windows Server 2012 (applies to newer versions as well).
Service Account Configuration:
The CiraSync On-Prem service account must be added to both your Windows Server and the CiraSync On-Prem UCM platform.

For detailed steps, refer to: Preparing Your Microsoft Windows Server for CiraSync On-Prem UCM.