I have a 2008R2 box with Backup Exec 2010R3 application running fine with all kind of Backup Agents NDMP,Microsoft,VMware
But when i choose to Add and new User Defind Selection for my QNAP NAS to backup a few shares i add the \\qnap1\
and it looks good i can successfuly browse all folders and check to backup any file.
Once i finish to check my requested files to backup i continue to Test User Credentials i get in reture Failed "a communications failure has occured"
cannot get passed this error.
And I would not recommnend to test credentials against CIFS shares. Instead run an actual backup and check if the backup fails or not.
Do ensure a remote agent license is installed for backing up CIFS and if this QNAP is capable of NDMP, you may want to disable NDMP or change the ndmp port 10000 for CIFS level backups.
I did try to run the backup and i always receive the same error with Credendials.
The Qnap is not capable of NDMP, i have the license for NDMP and my NDMP to Netapp works perfect.