Glossary: TCP/IP in Depth, Part 1
administratively prohibited
Also written: Packet filtered, !X, type 3 code 13
An ICMP destination unreachable error (type 3, code 13) that means a firewall refused the packet and said so. When the shop wouldn't load, ping showed it as "Packet filtered" and traceroute marked it !X, and both pointed at the office router.
Where the book teaches it
Related terms
destination unreachablefirewallICMP (Internet Control Message Protocol)