Have a look inside
<install_path>\VMware\VMware Consolidated Backup Framework\config\config.js
You used to have to tweak this file, but all config done in the snapshot policy configuration in the NetBackup GUI
Just check what the TRANSPORT _MODE is set to:
In this instance, I too use SAN transport and the config.js file shows the following ( // is comment)
// TRANSPORT_MODE="san";
Might be something overridding it and the mode nbd is being used.
Is this confirmed in the debug log files?
Turn verbose up to 5 on the proxy and create the following debug directories and
<install_path>/Veritas/NetBackup/logs/bpfis/
<install_path>/Veritas/NetBackup/logs/bpVMutil/
then browse through the output to see any clues why LAN is being used over SAN
