Glossary: TCP/IP in Depth, Part 1
destination unreachable
Also written: Destination Host Unreachable, type 3, !H, !N
ICMP type 3: a packet could not be delivered, and the code gives the reason (net, host, port, fragmentation needed or administratively prohibited). "Destination Host Unreachable" from your own address means ARP got no answer and the packet never left.
Where the book teaches it
Related terms
port unreachableadministratively prohibitedfragmentation neededICMP (Internet Control Message Protocol)