A NetScaler HA pair has a Secondary unit with state Unknown after moving to a new switch. What is the most likely cause?

A NetScaler HA pair has a Secondary unit with state Unknown after moving to a new switch. What is the most likely cause?

• A. The firewall is blocking communication between the switches.
• B. The administrator made both NetScalers Primary.
• C. The Secondary NetScaler CANNOT communicate in HA when moved to a new switch.
• D. The remote procedure call (RPC) nodes are NOT configured correctly.

Answer: (D)

In a NetScaler HA pair, both units stay in sync by exchanging heartbeat and state information over the HA link using RPC nodes. When the Secondary shows Unknown after moving to a new switch, the primary issue is that the two units cannot establish or maintain the HA session. The RPC nodes define how the peers communicate and where to send these heartbeat signals. If the RPC nodes aren’t configured correctly for the new network path, the units cannot reach each other, so the Secondary cannot determine its role and reports Unknown. This is why the best answer points to RPC nodes not configured correctly—that directly prevents the HA relationship from forming after a network change. While a firewall blocking the path could also cause communication issues, the root cause in this scenario is the misconfiguration of the RPC nodes. The remaining options either describe a symptom rather than a cause, or imply a situation that isn’t consistent with a typical HA state flip after a switch move.

In a NetScaler HA pair, both units stay in sync by exchanging heartbeat and state information over the HA link using RPC nodes. When the Secondary shows Unknown after moving to a new switch, the primary issue is that the two units cannot establish or maintain the HA session. The RPC nodes define how the peers communicate and where to send these heartbeat signals. If the RPC nodes aren’t configured correctly for the new network path, the units cannot reach each other, so the Secondary cannot determine its role and reports Unknown.

This is why the best answer points to RPC nodes not configured correctly—that directly prevents the HA relationship from forming after a network change. While a firewall blocking the path could also cause communication issues, the root cause in this scenario is the misconfiguration of the RPC nodes. The remaining options either describe a symptom rather than a cause, or imply a situation that isn’t consistent with a typical HA state flip after a switch move.