In IP networking terminology, what is a multi homed host and how is it connected to the network?

Introduction / Context:
Multi homing is a concept that appears in network design and reliability discussions. A multi homed host is designed to maintain connectivity through more than one network interface or network path. This question asks you to define a multi homed host and distinguish it from other network devices and configurations.

Given Data / Assumptions:

- We are dealing with IP hosts such as servers or workstations.- Multi homed implies some form of multiplicity in network connections.- The options describe different kinds of hosts and devices.

Concept / Approach:
A multi homed host is a single computer that has more than one active network interface card or port. Each interface can be connected to a different network segment or even to different service providers. The host will usually have multiple IP addresses, one for each interface. Multi homing can be used for redundancy, load sharing, or participation in multiple security zones. This is different from a router, which is dedicated to forwarding between networks, and from simple servers that have only one interface but many users.

Step-by-Step Solution:
Step 1: Recall that a host is an end system that runs applications and communicates over a network.Step 2: Multi homed suggests multiple homes or connections, hinting at more than one network attachment.Step 3: A multi homed host therefore is a single machine with multiple network interfaces, each potentially connected to a different network.Step 4: Option A states that such a host has more than one network interface and is connected to two or more networks with multiple IP addresses, which matches the standard definition.Step 5: Option B simply describes a dial up only host, which lacks permanent connectivity but does not define multi homing.Step 6: Option C describes an access point serving clients, which is a network device but not what multi homed host means.Step 7: Option D describes a router, which forwards packets and may have multiple networks, but the term multi homed host refers to an end host, not a router.Step 8: Option E describes a server with multiple user accounts but only one network interface, which is different from multi homing.

Verification / Alternative check:
Networking literature uses multi homed host to refer to servers that have connections to multiple networks or Internet service providers, often to increase reliability or handle more traffic. Examples include web servers with two network cards, each connected to a different switch, so that a switch failure does not disconnect the host. Security designs sometimes place multi homed hosts between different security zones but still treat them as hosts rather than full routers. These descriptions align with option A.

Why Other Options Are Wrong:
Dial up connectivity does not inherently involve multiple interfaces and is considered single homed. Wireless access points are infrastructure devices, not end hosts, and are not called multi homed hosts by standard terminology. Routers are multi interface but are classified separately, and the term multi homed router is used when appropriate. The number of user accounts on a host is unrelated to whether it is multi homed.

Common Pitfalls:
Some learners confuse multi homed hosts with routers or with hosts that simply serve many users. The key is to focus on the number of physical or logical network interfaces and the fact that the machine is an end host running normal applications, not solely performing packet forwarding. Remember that multi homed equals multiple network attachments, usually with multiple IP addresses.

Final Answer:
A multi homed host is a host with more than one network interface connected to two or more networks, usually with multiple IP addresses, as stated in option A.