An unknown ICMP message was received.

A required option is missing.

Incorrect parameters were supplied to TCP/IP.

A packet's time to live was exceeded.

A packet's source route failed.

A packet could not be sent because it had to be fragmented, and fragmentation is currently not allowed.

The port is presently unreachable.

The protocol is presently unreachable.

The host is presently unreachable.

The network is presently unreachable.