From NVBU 11.x, it is no longer possible to use the FQDN as NVBU server/client during the installation.
Product design has been changed from NVBU 11.x which prohibits use of FQDN during the installation.
It is possible to use the FQDN at installation only on versions prior to NVBU 11.x.
Use the nvclientname CLI command.
This command allows you to rename a NetVault Backup Client.
You cannot use this utility to change the name of a NetVault Backup Server as this is not supported.
The enhancement request to support FQDN as NetVault client name during installation has been submitted to the Product team under reference NV-I-434 .