Error Code: [39:424], [39:501] Description: Client [<client name>] was unable to connect to the tape server [<MediaAgent address>] on port <port number>]. Please check network connectivity. Source: <mediaagent name>, Process: NasBackup

This article provides guidance for resolving errors 39:424 and 39:501 (The Client was unable to connect to the tape server on port number...) and the possible causes of this error.

Symptoms

A backup or a restore operation for a NAS NDMP client fails with the following error message:

Error Code: [39:424] Description: Client [<client name>] was unable to connect to the tape server [<MediaAgent address>] on port <port number>]. Please check network connectivity. Source: <mediaagent name>, Process: NasBackup

Error Code: [39:501] description: Client [<client name>] was unable to connect to the tape server [<MediaAgent address>] on IP(s) [<IP address>] port [<port number>]. Please check the network connectivity. Source: <mediaagent name>, Process: NasBackup

Causes

When you run an NDMP backup or a restore job, a MediaAgent is chosen to run the job - this MediaAgent was able to connect to the file server to start the backup or a restore operation, but the connection for data transfer could not be established from the file server to the MediaAgent. Potential causes for this error are:

Firewall configuration between the file server and the MediaAgent does not have open ports or has too few open ports.
File server routing to the MediaAgent was not successful.
The wrong MediaAgent address was used for the transfer.
For NetApp file servers, the cluster node containing the data to backup does not contain an interface which can connect to the MediaAgent.
Incorrect MediaAgent was chosen for the job.

The NDMP control connection from the MediaAgent to the file server used to start the backup or a restore job typically uses the file server port 10,000 (configurable on the client NDMP properties dialog box) – this connection has succeeded so this port is open outgoing from the MediaAgent to the file server. For the data transfer, an additional connection is made from the file server to the MediaAgent. The MediaAgent will listen on open ports in the firewall configuration for this incoming connection from the file server. If no ports are configured in the firewall configuration or all configured ports are in use, any port on the MediaAgent will be used and the connection from the file sever to the MediaAgent might not succeed.

Resolution

If there is a firewall between the file server and the MediaAgent, verify that ports are open in the firewall. A range of ports must be open to handle parallel NDMP jobs. For more information about NDMP firewall configuration, see Configuring a Firewall Between a File Server and MediaAgent. For more information about port requirements, see Port Requirements for Commvault.
Check the file server side routing – file server vendor specific. Check the file server configuration (i.e., the routing tables) to verify that it is configured to be able to access the MediaAgent address. For NetApp file servers, the NetApp cluster will choose an interface based on the vserver ndmp “preferred interface role” setting which defaults to 1.intercluster 2.cluster-mgmt 3.node-mgmt.
If the incorrect MediaAgent address is used, consider adding a data-interface-pair (DIP). A MediaAgent might have several interfaces on different subnets. For the data transfer, the MediaAgent will listen on all interfaces for the incoming connection from the file server, and the file server must try each interface in turn until one succeeds. The connection from the MediaAgent to the file sever to start the job succeeded so there must be a valid interface between the MediaAgent and the file server. To specify a specific MediaAgent interface to use for the data transfer, you can use a DIP. For more information about configuring a dedicated backup network using DIPs, see Configuring a Dedicated Backup Network Using Data Interface Pairs.
For NetApp file servers, add an interface to the cluster node which can connect to the MediaAgent.~~~~
If an incorrect MediaAgent has been chosen, confirm the NAS client configuration. The MediaAgent for a job is chosen as follows:

When you run an NDMP backup or restore job, a MediaAgent is chosen to run the job. In a typical NDMP configuration, the MediaAgent is chosen from the plan or the storage policy associated with the backup.
Alternatively, an access node can also be associated with the NDMP agent under a NAS client. Such a configuration is useful when the plan or the storage policy MediaAgents do not have access to the file server or have lower performance access. In this configuration the MediaAgent is chosen from the access node configuration when performing the backup or restore operations.
In a Metallic configuration, the Metallic backup gateway can be set as the access node on the NDMP agent under the NAS client. This gateway is chosen as the MediaAgent to communicate with the file server. For more information about the Metallic backup gateway, see Metallic Backup Gateway.