- If the identity of a remote endpoint is delivered as URI only, Cisco Unified Communications Manager replaces the host portion of the URI with the IP address of the local call control server.
- To deliver a SIP message with the originally used host portion, at all outbound devices (endpoints and trunk) along the path, the Use Fully Qualified Domain Name SIP profile parameter must be set to Enable.
By default, Cisco Unified Communications Manager replaces the host portion of a remote endpoint directory URI with the IP address of the local Cisco Unified Communications Manager server that routes the call when the identity of the remote endpoint is delivered as URI only. The host portion is not changed if no URI is delivered, and it is also not changed when blended addressing is used. The host portion is also not changed if the call is placed within a cluster.
If you want to deliver the actual directory URI of the remote endpoint to a local phone, you must set the Use Fully Qualified Domain Name SIP profile parameter to Enable. The parameter must be applied at all outbound devices (SIP trunks and the terminating phone) along the path. If you want to use the FQDN for the presentation of the remote endpoint at both endpoints, then you must apply the parameter at all outbound devices along the paths of both directions. To achieve this setting, you have to apply the parameter at all (inbound and outbound) devices along the path.
If you use blended addressing in one direction, then you do not need to apply the Use Fully Qualified Domain Name parameter to the outbound devices in the direction of the endpoint that receives the blended addresses. Cisco Unified Communications Manager only replaces the host portion with a local server IP address if it receives a URI only.