by default FTD hostname is firepower#
how to change
ssh to FTD
bash
> config network hostname A22-33U-DS-BGP-FW-3150-1
the hostname will show when system support diag
bash
> system support diagnostic-cli
Attaching to Diagnostic CLI ... Press 'Ctrl+a then d' to detach.
Type help or '?' for a list of available commands.
A22-33U-DS-BGP-FW-3150-1>