This site requires JavaScript for navigation. Please enable JavaScript for the best learning experience.

When a datagram is being forwarded, and reaches a gateway attached to the network a destination host is to be found on, and the route to the host is down, the host is not responding or does not respond on the service port in question, a Host Unreachable message is sent back.

This message is usually displayed as a 'U' in a ping result, and as '!H' in a traceroute result.


Bookmark this page and SHARE:  


Support InetDaemon.Com

Get Tutorials in your INBOX!

Free Training