What field in the IP header can be used to ensure that a packet is forwarded through no more than N routers?

The field in the IP header used to ensure that a packet is forwarded through no more than N routers is the "Time to Live" (TTL) field. The TTL value is decremented by each router that forwards the packet, and if it reaches zero, the packet is discarded. This mechanism prevents packets from circulating indefinitely in the network due to routing errors. By setting the TTL to a specific value, a sender can effectively control the maximum number of hops a packet can take.