The following behaviors have been reported when backing up clustered resources that are present to the Backup Exec media server on multiple networks:
This is fixed in Hotfix 161270 (See Related Articles Section)
Unfortunately the specifics of any workaround for this problem depend on the exact environmental configuration of the secondary networks in the servers, nodes and cluster resources, as such the following provides a list of items for consideration rather than specific steps:
1) If protecting a cluster, the shared Cluster resources must have an IP address on the backup network in addition to the address on the main network.
2) If Remote Agent publishing/advertising is enabled on the server or nodes of the cluster, then use a User Defined Selection of just the IP Address (i.e. \\192.168.1.50)
3) If Remote Agent publishing/advertising is disabled on the nodes then use User Defined Selections of FQDN or DNS (short) names but make sure that name resolution for any servers, nodes and cluster resources does resolve to the correct address for the Backup LAN (which in most configurations would need a host file change on the media server so as to not affect DNS for systems not on the Backup LAN)
4) Specify the NIC of the Backup LAN in the "Network Interface" drop down inside the "Network and Security" section of the Backup Job properties.
NOTE: It helps if the network interfaces have been given useful names in the operating system of the media server.
5) Enable the option "Allow use of any available network interface, subnet, or protocol for remote agents not bound to the above interfaces, subnet or protocol"
Note: Enabling this option appears to be incorrect against the desired result, however the Backup Exec problem relates to the logic used to detect that a resource is available on a specific network. As the logic returns an incorrect error condition even when it can use the specified network, enabling this option, running the backup job and then reviewing the established network connections in the backup job logs will show that both control and data connections have used over the backup network.