The Expired TTL Message
The Time to Live (TTL) is an important consideration in understanding the ping command. The function of the TTL is to prevent circular routing, which occurs when a ping request keeps looping through a series of hosts. The TTL counts each hop along the way toward its destination device. Each time it counts one hop, the hop is subtracted from the TTL. If the TTL reaches 0, the TTL has expired, and you get a message like the following:
Reply from 24.67.180.1: TTL expired in transit
If the TTL is exceeded with ping, you might have a routing problem on the network. You can modify the TTL for ping on a Windows system by using the ping -i command.