Which ports must remain open to support replication between two Prism Element clusters?

Replication between Nutanix clusters involves the transfer of both actual data blocks and the metadata required to manage the consistency and scheduling of those snapshots. Two specific services running on the Controller VMs (CVMs) are responsible for these tasks: Stargate and Cerebro.

Port TCP 2009 is used by the Stargate service. Stargate is the primary I/O manager for the Nutanix cluster, and in a BCDR context, it handles the " Snapshot-on-wire " data transfer. This is the port where the actual bits of the virtual disks are sent from the source cluster to the destination cluster. Port TCP 2020 is used by the Cerebro service. Cerebro is the replication engine that handles protection domain orchestration, snapshot scheduling, and cross-site handshake operations. Without port 2020, the clusters cannot synchronize their schedules or confirm that a recovery point has been successfully stored at the remote site. While other ports like 9440 (Prism management) and 22 (SSH) are used for administrative tasks, ports 2009 and 2020 are the mandatory " data path " and " control path " ports required for the continuous and successful replication of workloads between availability zones.