you did not state which version of Vertias you are on.
But i do have experience with Symantec Backup Exec ver 12, new name for Vertias.
For symantec backup exec 12,
1. Select the particular backup job for your exchange server.
2. Right Click -> Properties on the Job.
3. In the left panel, Choose under Settings, Network & Security
4. In the right panel, there is a dropdown list box labeled "Network_Interface"
Under this option, you get to choose from all the installed network adapters (eg GLAN / LAN or WIFI cards ) in the system.
By default, it is set to use any network interfaces available.
Please select the required adapter which has access to your exchange server.
If necc, please do a ping test to ensure there is a working communication route.
If your exchange server work on different subnet as commented by Aegil, you might need to configure your GLAN adapter's network configuration before configuring your Veritas Job.
