Enforce SIP Client Authentication by SIP Proxy

When the device is located between a SIP client and a third-party SIP proxy server and SIP Digest Authentication is used, the device relays authentication messages between these entities. Although the device gathers and maintains some information in its registration database (Address of Record / AOR) it does not actively participate in the authentication process. Instead, it's the SIP proxy that handles and enforces SIP client authentication. Therefore, it's imperative that your SIP proxy server be configured to enforce SIP client authentication.