Cisco Certified Network Associate (CCNA) 2026 – 400 Free Practice Questions to Pass the Exam

The conditions required for EIGRP for IPv6 routers to establish a neighborship are centered around certain critical factors that ensure both routers can effectively communicate.

Firstly, both routers must have their interfaces in an "up/up" state. This means that the physical layer and data link layer of the interfaces must be functioning properly so that packets can be transmitted and received.

Secondly, both routers need to be configured with the same Autonomous System (AS) number. EIGRP is designed to operate within a specific AS, and if the numbers do not match, the routers will not form a neighborship, as they are effectively seen as operating in different routing domains.

In addition to the above, the K values, which determine the metrics used for EIGRP's route selection process, must also be the same. Any discrepancy in these values would mean that although the routers could technically communicate, they would be using different formulas to evaluate their routing decisions, leading to potential routing inconsistencies.

Lastly, having the same authentication settings is crucial, especially in environments where EIGRP authentication is configured. Disparate authentication setups would prevent the routers from establishing a secure connection.

Thus, the correct answer confirms that the interface status must be up, the AS numbers