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Summary:This article provides information about the ports that maintain the cluster state and the importance of ARP.
Problem or Goal:Information about the ports that maintain the cluster state and the importance of ARP.
Solution:There are several KB articles, which list all the ports that are involved with SA/UAC clusters. However, at times, it is required to specifically know which ports maintain the cluster state.
- ARPAt times, this protocol is forgotten during cluster state checks/investigations. The ARP requests/replies are important to a SA cluster, as ARP’s are sent to the gateway of the subnet, to which the VIP of the cluster belongs, to maintain reach-ability to the subnet gateway.
- UDP 4803The state data replication, which refers to all data that must be replicated between cluster nodes. Examples include a user session record, when session synchronization has been enabled between cluster members (see the UI cluster properties page) and the cluster-wide configuration.
- UDP 4804 – Heartbeat.
You should always check the ARP tables, when investigating/checking a cluster state, along with the other two ports listed above; as all the above ports are important for maintaining a cluster state.
What TCP and UDP ports are required/used for clustering and what is each port used for?
|TCP 4808||Cluster heartbeats and intra cluster RPC calls||Yes|
|TCP 4809||Clustering on. Used to query the build version being run at the remote IVE||No|
|TCP 4900-4910||For a short period when a node joins the cluster Key exchange for group communication, state sync where applicableMostly copying the state data from one cluster node to another when a node joins the cluster or when a cluster rejoins after partition. There should be significant data only on one these ports||Yes|
|UDP 4803||Clustering On, always Group communication. Incremental state data replication.||Yes|
|UDP 4804||Clustering On, always Token Heartbeat. Group communication heartbeats. No data on this channel.||No|