Exam 200-301 topic 1 question 169 discussion

Private IPv4 addresses weren't created to be a form of protection. It's primary purpose was to enable internal networks to communicate while conserving public IPv4 addresses. A fits this narrative as multiple businesses could share the same private IP addresses and their application would still be able to communicate without interfering with other businesses thus it's unique to their internal applications. E for obvious reasons. D doesn't work because if you have servers that need to be reached from the outside you would have it port forwarded and thus having it exposed to the internet and DoS. Even if you don't have internal services advertised to the internet, attackers can still DoS your gateway because it has a public IP address.

"To enable internal applications to treat the private IPv4 addresses as unique" This describes layer 2 functionality, mac address, arp tables. So i think it's wrong.

B. To facilitate renumbering when merging networks – Using private IPv4 addresses allows easier renumbering when networks merge, as they do not conflict with global addresses assigned by an ISP.

Could someone please translate answer A into human's language? What does 'enable internal applications treat private IPv4 addresses as unique' mean? What's the difference between the above sentence and 'enable miserable apples treat public IPv9 dogs as Hollywood'?

Seems A is not clear a public ip can do that too

Only A and E are correct

A & E are most correct

Some of the reasons to implement IPv4 private addressing on a network are: To conserve global unique IPv4 addresses : Since there is a limited supply of public IP addresses, private IP addresses provide an entirely separate set of addresses that allow access on a network without taking up a public IP address space. This way, multiple devices in a network can share a single public IP address for communication with the Internet, while using private IP addresses for communication within the network. To facilitate renumbering when merging networks : Private IP addresses are not allocated to any specific organization, and anyone may use these addresses without approval from regional or local Internet registries. This makes it easier to renumber the devices in a network when two or more networks are merged, as there is no need to coordinate with external authorities or update the routing information on the Internet.

It's D & E. A is incorrect. It's nonsensical. Let's break it down: "To enable internal applications to treat the private IPv4 addresses as unique " Internal applications treat *all* IPv4 addresses as unique; public or private addressing schemes are irrelevant. Internal applications only care insofar as the IPv4 address is valid and routable; network topology does not matter. Even if you disregarded this, private IPv4 addresses are arguably *less* unique than their public counterparts, simply because multiple organizations can deploy the same addresses internally. D. is correct, because preventing internal hosts from being accessible from an external WAN means they're protected from *external* DOS, i.e. TCP SYN floods, simply because they can't be externally accessed. This is absolutely a reason to implement private addressing schemes. E. is correct for obvious reasons.

In fact, external DOS attacks occur not to the devices to which you have assigned a private IP, but to your servers to which you have assigned a public IP. So it should be AE

I don't think A&E are correct

These two are the best

The two reasons to implement IPv4 private addressing on a network are B & E: To facilitate renumbering when merging networks. When two networks are merged, it can be difficult to renumber all of the devices on the networks to use the same public IPv4 address space. Using private IPv4 addresses on the two networks before the merge makes it easier to renumber the devices after the merge. The other options are not reasons to implement IPv4 private addressing on a network. Option A: Internal applications will treat the private IPv4 addresses as unique regardless of whether or not they are implemented on the network. Option B: Renumbering when merging networks can be facilitated by using private IPv4 addresses, but it is not the main reason to implement private IPv4 addressing. Option C: Private IPv4 addresses do not expand the routing table on the router. Option D: Private IPv4 addresses do not provide protection from external denial-of-service attacks.

B and E, according to AI

DE is correct

not for protection, to preserve public ip and easier internal network communication.

A. To enable internal applications to treat the private IPv4 addresses as unique: Private addressing allows organizations to use non-routable IP addresses internally, which are not globally unique. This enables internal applications, services, and devices to communicate with each other using unique addresses within the private network without conflicting with globally routable IP addresses. E. To conserve global unique IPv4 addresses: The availability of globally unique IPv4 addresses is limited. By implementing private addressing, organizations can conserve the limited pool of global unique IPv4 addresses. Private addresses are not publicly routable on the Internet, so they can be reused within different private networks without consuming additional global address space. Options B, C, and D are not reasons to implement private addressing on a network: