Exam MTCNA Topic 9 Question 166 Discussion

When ARP is set to reply-only on a MikroTik interface, the router will not respond to any ARP requests unless a matching static entry exists in the /ip arp list. It will also not learn new dynamic entries - only pre- defined static IP-MAC pairs will be accepted and responded to.
Option breakdown:
* A.#Incorrect - The router doesn't operate solely based on MAC, but on IP-MAC pairings.
* B.#Correct - Only combinations that match entries in /ip arp are accepted.
* C.#Incorrect - reply-only mode disables dynamic ARP learning.
* D.#Incorrect - Again, no new IPs are dynamically added.
* E.#Incorrect - Static ARP is enforced by IP-MAC pairs, not just IP.
Extract from MTCNA Course Material - ARP Modes:
"Reply-only mode will respond to ARP requests only if a matching static ARP entry exists. No dynamic learning occurs." Extract from Rene Meneses Study Guide - ARP Explanation:
"Use ARP=reply-only to force strict IP-MAC pairing. It prevents spoofing but requires all valid pairs to be preconfigured." Extract from MikroTik Wiki - ARP Settings:
"reply-only: Only respond to ARP requests if the requester matches a static /ip arp entry. New dynamic entries are not created."