Technical data

Using the Ping Option
117347-A Rev. A 11-5
Figure 11-4. Ping Does Not Respond Window
• An “ICMP host unreachable from <y.y.y.y>” message
An “ICMP host unreachable from <y.y.y.y>” message appears if the router
whose address is y.y.y.y cannot forward the ping request any further along the
path to the target device. IP updates its IP routing or Address Resolution
Protocol (ARP) table accordingly. A sample message follows:
ping: ICMP host unreachable from 192.32.243.1
• A target address “is unreachable” message
A target address “is unreachable” message appears if the router previously
issued an “ICMP host unreachable from <y.y.y.y>” message. Within
40 seconds, the router receives a subsequent ICMP echo request addressed to
the same target device. The ARP times out or the address is not resolved. A
sample message follows:
ping: 192.32.1.151 is unreachable