CB Exchange Server Sync

CB Exchange Server Sync lets you securely sync or migrate email, calendars, contacts and tasks across Exchange, Microsoft 365 and Gmail—without downtime or storing mailbox content.

• Server-side, zero content retention – No mailbox data stored on third-party servers; content stays under your control.

• Cross-tenant, cross-domain, cross-version – Works with Exchange 2013/2016/2019/Online, Microsoft 365, Gmail and hybrid setups.

• Flexible deployment – Self-hosted or SaaS (cloud) to meet any data-residency or compliance requirement.

• Enterprise-grade security – Uses TLS 1.2, OAuth 2.0, MFA; supports GCC High and even data-diode architecture for one-way sync.

• Scalable & fast – Proven in migrations with thousands of mailboxes and millions of items, with near-real-time sync.

• Trusted - by enterprises, government agencies, and regulated industries worldwide.

• For ongoing synchronization

  • Keeps mailboxes, calendars, contacts, and tasks perfectly aligned across Exchange, Microsoft 365, Gmail, or mixed environments.

  • Reduces manual updates and support tickets, saving IT time and recurring labor costs.

  • Improves productivity by giving users consistent, always-up-to-date information.

• For one-time migrations

  • Cuts project time and downtime to near zero, so staff stay productive during the move.

  • Lowers consulting and overtime costs, and minimizes revenue loss from outages.

  • Reduces compliance risk (GDPR, HIPAA, government standards) and potential penalties.

The result is lower total cost of ownership and a faster ROI, often within the first project or sync cycle.

Syncing mail can mean one of two things:

1. Synchronize one account from the server to the client – This means getting the email items, namely the messages or calendar items, from the server to client devices.
2. Synchronize multiple email accounts - This is the case covered by CB Exchange Server Sync: you have two e-mail accounts, and synchronization will allow you to choose one of them as a “origin account” and the other one as the "target account". All the information is automatically copied from the origin to the target account. This way you can check all of your email messages, calendar items and more from a single location. You can also do the same bidirectionally and for multiple pairs of accounts.For more details, check this article.

You can set the frequency of synchronization by defining Polling Interval inside the SaaS dashboard.
Polling Interval determines how often the synchronization service checks for changes to perform since the last synchronization on the Exchange Server.

PLEASE NOTE: A shorter interval results in faster and more precise synchronization. If you have chosen a SaaS deployment, beware that a shorter interval increases traffic.

Yes. Moreover, migrating mailboxes is great with CB Exchange Server Sync, as you can work with both accounts in parallel and do it in iterations or batches if needed. 

Yes. CB Exchange Server Sync can synchronize:

• Public folders
  Public folders can also be mapped to normal user mailboxes if needed, and cross-tenant or cross-domain scenarios are supported.
  

• Shared mailboxes
  The setup is similar to standard mailboxes: you specify the source and target folders in the sync configuration and assign the service account the necessary access rights. 

CB Exchange Server Sync covers almost all mailbox content, including emails, calendar events, contacts, tasks, and attachments.
There are a few expected exclusions:

• Exceptionally large individual items that might not be supported by the destination Exchange Server 
• Recoverable Items / Deleted Items versions are not included, as they are outside the normal mailbox scope. You can, however, configure the solution to take into account your retention policies.

In practice, these exceptions do not affect day-to-day mailbox synchronization.

You can choose between two models:

• Subscription license (per sync pair, per month or year) – best for flexibility and OPEX budgeting.
• Perpetual license (one-time purchase per sync pair) – best for long-term ownership and CAPEX budgeting.

License activation is straightforward: after installation, you request a license, and then activate it. 

For successful synchronization, it is essential to know the exact Exchange Server version you have. You can find it by:

• Asking your IT administrator or hosting provider – They can quickly confirm whether you use on-premises Exchange (e.g., 2016, 2019) or Microsoft 365 Exchange Online.

• Following Microsoft’s official instructions – Use their guide to locate and match your server’s build number with the correct version: Microsoft Support

Yes, you can. CB Exchange Server Sync can operate even in strictly isolated or classified environments when paired with hardware data diodes, allowing you to safely synchronize Exchange data in a controlled, one-way direction.

This setup is ideal for organizations in defense, government, or highly regulated industries that require complete separation between systems. It ensures data integrity and confidentiality while still keeping calendars, contacts, and tasks aligned across environments.

The same principle can also scale to more advanced configurations, as you can see on the specific page CB Exchange Server Secure Sync with Data Diodes