What happens to the Time to Live (TTL) value each time a packet passes through a router?

• A. It is incremented by one.
• B. It is reset to the original value.
• C. It is decremented by one.
• D. It is removed from the header.

Answer: (C)

Time to Live is a field in the IP header that prevents packets from looping forever. It’s set by the sender and then decreased by one each time the packet passes through a router. This hop-by-hop decrement continues until the TTL reaches zero, at which point the router drops the packet and typically reports back with an ICMP Time Exceeded message. It isn’t incremented or reset along the way, and it isn’t removed from the header—the value simply diminishes with each hop.