What will a router do with a packet that has a TTL of 1?

• A. Accept or drop, but not forward
• B. Forward the packet as usual
• C. Increment TTL and forward
• D. Broadcast to all interfaces

Answer: (A)

TTL (Time To Live) controls how many routers a packet can pass through. Each router that forwards the packet decreases TTL by one. If TTL reaches zero, the router must drop the packet to prevent looping. With a TTL of 1, the first router will reduce it to 0 and stop the packet, so it is not forwarded (often an ICMP Time Exceeded message is sent back to the sender). So the correct outcome is that the packet is dropped, not forwarded.