Communication with clients other than NAT clients
When NAT support is enabled on a NetBackup server, the default behaviour of the server is to perform all client connections via the NetBackup messaging broker service on the master server. This requires all clients that the server communicates with to have NAT support enabled. In this default configuration, the server will fail to communicate with any clients that have NAT support disabled or those running a version of NetBackup lacking NAT support. It is possible to instruct the server to attempt a direct connection to such clients by setting the ENABLE_DIRECT_CONNECTION option to TRUE. Setting this option allows a NetBackup server to work with clients that have NAT enabled (using reverse connections) and those that have NAT disabled (using direct connections).
In an AIR setup, both source and target master servers must be enabled for direct connection.