The RARP protocol sends out a packet, which includes its MAC address and a request to be informed of the IP address that should be assigned to that MAC address.
ARP does the opposite by broadcasting a request to find the Ethernet address that matches a known IP address.
ICMP supports packets containing error, control, and informational messages (e.g. PING). UDP runs over IP and is used primarily for broadcasting messages over a network.
Source: KRUTZ, Ronald L. & VINES, Russel D., The CISSP Prep Guide: Mastering the Ten Domains of Computer Security, 2001, John Wiley & Sons, Page 87.

ARP interrogates the network by sending out a broadcast seeking a network node that has a specific IP address, and asks it to reply with its hardware address. A broadcast message is sent to everyone whether or not the message was requested. A traditional unicast is a “one-to-one” or “narrowcast” message. A multicast is a “one-to-many” message that is traditionally only sent to those machine that requested the information. Semicast is an imposter answer. Source: KRUTZ, Ronald L. & VINES, Russel D., The CISSP Prep Guide: Mastering the Ten Domains of Computer Security, 2001, John Wiley & Sons, Page 87.

ARP is used to find the Media Access Control address (MAC) that matches with a known Internet Protocol (IP) address.
The Address Resolution Protocol (ARP) is a computer networking protocol for determining a network host’s link layer or hardware address when only its Internet Layer (IP) or Network Layer address is known
Reverse Address Resolution Protocol (RARP) is used to find the IP address that matches an Ethernet address.
ICMP is a management protocol and messaging service provider for IP (e.g. PING). UDP runs over IP. It is a best effort protocol that offers no reliability. UDS is used for application such as streaming media, voice over IP, the DNS protocol, as well as the Simple Network Management Protocol (SNMP).
Source: KRUTZ, Ronald L. & VINES, Russel D., The CISSP Prep Guide: Mastering the Ten Domains of Computer Security, 2001, John Wiley & Sons, Page 87. also see: http://en.wikipedia.org/wiki/Address_resolution_protocol

IPv4 addresses are currently 32 bits long. IPv6 addresses are 128 bits long. Source: KRUTZ, Ronald L. & VINES, Russel D., The CISSP Prep Guide: Mastering the Ten Domains of Computer Security, 2001, John Wiley & Sons, Page 87.

Each data packet is assigned the IP address of the sender and the IP address of the recipient. The term network refers to the part of the IP address that identifies each network. The terms host and node refer to the parts of the IP address that identify a specific machine on a network.
Source: KRUTZ, Ronald L. & VINES, Russel D., The CISSP Prep Guide: Mastering the Ten Domains of Computer Security, 2001, John Wiley & Sons, Page 87.

All hosts on a network have a logical ID that is called an IP address. An IP address is a numeric identifier that is assigned to each machine on an IP network. It designates the location of a device on a network. A MAC address is typically called a hardware address because it is “burned” into the NIC card. TCP address and Datagram address are imposter answers.
Source: KRUTZ, Ronald L. & VINES, Russel D., The CISSP Prep Guide: Mastering the Ten Domains of Computer Security, 2001, John Wiley & Sons, Page 87.

When using packet switching, messages are broken down into packets. Source and destination address are added to each packet so that when passing through a network node, they can be examined and eventually rerouted through different paths as conditions change. All message packets may travel different paths and not arrive in the same order as sent. Packets need to be collected and reassembled into the original message at destination.
Source: TIPTON, Hal, (ISC)2, Introduction to the CISSP Exam presentation.

A bastion host is a special purpose computer on a network specifically designed and configured to withstand attack. The computer hosts a single application, for example a proxy server, and all other services are removed or limited to reduce the threat to the computer. It is hardened in this manner primarily due to its location and purpose, which is either on the outside of the firewall or in the DMZ and usually involves access from untrusted networks or computers.
References: http://en.wikipedia.org/wiki/Bastion_host

The main characteristic of a multi-homed host is that is has multiple network interfaces, each connected to logically and physically separate networks. IP routing should be disabled to prevent the firewall from routing packets directly from one interface to the other.
Source: FERREL, Robert G, Questions and Answers for the CISSP Exam, domain 2 (derived from the Information Security Management Handbook, 4th Ed., by Tipton & Krause).

SMTP (Simple Mail Transfer Protocol) works as a message transfer agent. Source: HARRIS, Shon, All-In-One CISSP Certification Exam Guide, McGraw-Hill/Osborne, 2001, Page 821.