18. ________ is a debugging tool that is a program that gets help from two error reporting messages: time-exceeded and destination-unreachable.

a. traceroute

b. ping

c. findip

d. destination-ip

19. In link-state routing, each router tells __________ what it knows about _______.

a. the whole internet, its neighbors

b. its neighbors, the whole internet

c. its neighbor, its neighbors

d. the whole internet, the whole internet

20. _________ involves intercepting a packet, changing the contents and sending the new packet to the receiver,

a. Packet modification

b. packet sniffing

c. packet snuffing

d. IP spoofing

22. ___________ involves intercepting a packet and making a copy of it.

a. packet sniffing

b. packet snuffing

c. packet modification

d. IP spoofing