Can PPPoE and DHCP be used on the same interface?

• A. No
• B. Yes, but not on the same network
• C. Yes
• D. Only if the interface is in bridge mode

Answer: (C)

PPPoE and DHCP operate on different layers and can coexist on the same physical link because PPPoE creates a separate logical interface on top of that link, while DHCP provides IP configuration to devices inside your LAN. The PPPoE session handles the connection to the ISP and gets its own IP via the PPP session, and DHCP can still run on the router to assign addresses to devices behind it. In practice, you often have the PPPoE uplink on the WAN side and a DHCP server on the LAN side (often via a bridge), all sharing the same physical port without conflict.