Exam 300-420 topic 1 question 5 discussion

A is not correct. You wouldn't create a NAT to convert every single user from the newly acquired company into one IP address in the other existing company. You would create a static NAT for traffic destined to the server at the network boundary between the 2 companies. Traffic destined to the server from the newly acquired company would be NAT'd to the server IP in Company A.

If A company client use net A (10.0.0.0/24) if B company client use net A (10.0.0.0/24) if server is on net S (172.16.0.0/24) Client form B must masquerade their source to avoid backward traffic (backward of traffic originated from company B client that reached the servers) goes to Company A. so A is OK.

this is a tricky question, many users require to access a server so from source side (clients) point of view, it could be overloading NAT, configuration is simple; or 1 to 1 static NAT for all users also possible. from destination side (server), it may require a static NAT (simple), or a port forwarding NAT in a overloading NAT setup. And according to the question, "Which action conserves IP address space and provides access to the server?" I beleive asking which NAT solution allows client to access to the server so A is correct. or in another way to understand, overloading NAT is able to use in both side, so A is most possible correct one. For B, it only corrects in server side, but on client side, need many static NAT entries

one to one for the server

Here's why: B. Use a single IP address to create a static NAT entry: It's not specific enough, create a Single IP Static NAT Entry of what ? it doesn't specify anything or say it's for the server and it needs to be very clear. C. Build one-to-one NAT translation for every user that needs access: This is not feasible, you are not going to create a Static NAT for every host so this is wrong. D. Re-IP overlapping address space in the acquired company: When you acquire a company with overlapping networks you want to try to avoid re-IP the entire network initially. The question also states you want to keep the same IP Subnet space which means you want to keep things as it is so a redo of IP Subnets is not an option. Leaves us with the only correct answer which is A. It can also be found on the OCG Book on page 15

Why not D. Re-IP overlapping address space in the acquired company ?

A is correct.

I think the big question here is what adresses reside on both global and local site. Is it the address of the server (answer B) or the clients (answer A).

B seems better option

Answer is B.

Provided answer is correct