Which port is used for inter-NetScaler traffic in high-availability troubleshooting?

• A. 3009
• B. 443
• C. 80
• D. 22

Answer: (A)

Inter-Netscaler high-availability relies on a dedicated internal channel where the two units exchange status, heartbeat signals, and synchronized state. This inter-device communication keeps the active and standby units in sync and helps detect and manage failover quickly. The port used for this internal HA traffic is 3009, which means when you’re troubleshooting HA problems you check that connectivity on this port between the two NetScaler nodes is open and responsive. The other ports serve client or management traffic—443 for HTTPS management, 80 for HTTP, and 22 for SSH—so they don’t govern the inter-unit HA communication. Ensuring port 3009 can reach across the pair is essential for reliable failover and synchronized configuration.