Which of the following is true about bridging PPP tunnels on a router?

• A. All PPP-based tunnels can be bridged
• B. No bridging for PPP tunnels
• C. Bridge only works for VLANs
• D. Cannot bridge tunnels without enabling bridging

Answer: (A)

Bridging works by joining multiple interfaces at layer 2 into one shared ethernet-like domain. A PPP tunnel is just another data-link layer interface, so RouterOS can include it in a bridge along with your physical LAN interfaces. Once the PPP tunnel is added to the bridge, devices on the local side can reach devices on the remote side as if they’re on the same Ethernet segment, and MAC learning and ARP broadcasts can flow across the tunnel. Because a PPP-based tunnel is an ordinary L2 interface, there’s no inherent restriction preventing it from being bridged, so you can bridge PPPoE, PPTP, L2TP, and other PPP-based tunnels. In practice, when you bridge, you’ll manage IP addressing and DHCP at the endpoints or on the bridge as needed, and you should watch out for potential loops and MTU considerations, but bridging PPP tunnels is supported and often used to extend a LAN across a VPN.