Prerequisites and setup steps
Prerequisites
To set up and run the integration, the following requirements must be met:
Access to the Azure Portal
An enterprise application must be enabled for querying Graph API, including:
TenantID,ClientID, andClientSecret(with renewal options or an "endless certificate")Read access to required Graph API parameters
The following Azure functionalities must be enabled:
Azure FunctionsResource GroupBlob Storage
Access to Entra ID / Microsoft 365 / Exchange Online User Administration Portal
Visual Studio Code (latest version)
Required extensions, such as Azure Functions
Retarus DirSync via HTTPS Push
Basic authentication credentials provided by Retarus
Secure HTTPS URL provided by Retarus
Supported configurations
✔️ Sync customer-owned fax numbers that have been ported to Retarus
✔️ Sync fax numbers purchased by Retarus on behalf of the customer
✔️ Sync SIP trunk numbers
✔️ Sync forwarding configurations (B-number and C-number)
✔️ Sync alphanumeric CSID (for Email-to-Fax)
✔️ Sync users with multiple fax numbers (comma-separated, for Fax-to-Email)
✔️ Sync extension-prefix configurations where fax numbers are derived from phone numbers
Example
Phone:
+49 123456 – 1234Fax:
+49 123456 – 10 – 1234
→ Extension-prefix ="10"
✔️ Sync users who:
Have one or more direct fax numbers
andHave a forwarding setup in place
(e.g., administrators using a SIP trunk in the headquarters but requiring forwarding to a fax infrastructure in another country)
✔️ Sync fax numbers with multiple recipients