At what point would a router stop forwarding the packet during a tracert?

In a traceroute operation, a router will stop forwarding a packet when the Time to Live (TTL) value reaches zero. TTL is a field in the IP packet header that helps prevent packets from circulating indefinitely in case of routing loops. Each time a packet passes through a router, the router decrements the TTL value by one.

When the TTL reaches zero, the router recognizes this condition and discards the packet to prevent it from being forwarded further. At this point, the router typically sends an Internet Control Message Protocol (ICMP) Time Exceeded message back to the source, indicating that the packet could not be delivered because it expired on its journey.

This mechanism is critical for diagnosing path issues in networks, as it helps identify the routers involved in the route to the destination. Thus, the correct answer highlights a fundamental aspect of how TTL functions within the context of network routing and packet forwarding behavior.