Which configuration on the Expressway is needed for a SIP end point to register?

= The Expressway can act as a SIP registrar for up to 200 domains. To make the Expressway act as a SIP registrar, you must configure it with the SIP domains for which it will be authoritative. It will then handle registration requests for any endpoints attempting to register against that domain. To configure a SIP domain on the Expressway, go to Configuration > Domains and click New. Enter the domain name and select whether the Expressway or the Unified CM provides registration and provisioning services for the domain. You can also configure other options such as authentication, encryption, and call policy for the domain. After adding the domain, you must restart the Expressway for the changes to take effect. A SIP endpoint that wants to register with the Expressway must use a SIP URI that matches one of the configured domains on the Expressway. For example, if the Expressway is configured with the domain example.com, the endpoint must use a SIP URI like user@example.com to register with the Expressway. References := Cisco Expressway Administrator Guide (X14.0) - Configuring DomainsCisco Expressway Basic Configuration Deployment Guide (X14.0) - Configuring SIP Domains