Configuring the PPPoE Trusted Interface
Context
To prevent bogus PPPoE servers and the security risk caused by PPPoE packets forwarded to non-PPPoE service interfaces, the interface connecting the Switch and the PPPoE server must be configured as the trusted interface. Then PPPoE protocol packets are forwarded to the PPPoE server through the trusted interface only. In addition, only the PPPoE protocol packets received on the trusted interface can be forwarded to the PPPoE client.
The trusted interface controls PPPoE protocol packets at the PPPoE discovery stage only. PPPoE service packets at the PPPoE session stage are not controlled.