A teardrop attack is a denial-of-service (DoS) attack that involves sending fragmented packets to a target machine. Since the machine receiving such packets cannot reassemble them due to a bug in TCP/IP fragmentation reassembly, the packets overlap one another, crashing the target network device. This generally happens on older operating systems such as Windows 3.1x, Windows 95, Windows NT and versions of the Linux kernel prior to 2.1.63.

Each of the ASAs interfaces need to be grouped into one or more bridge groups. Each of these groups acts as an independent transparent firewall. It is not possible for one bridge group to communicate with another bridge group without assistance from an external router.
As of 8.4(1) upto 8 bridge groups are supported with 2-4 interface in each group. Prior to this only one bridge group was supported and only 2 interfaces.
Up to 4 interfaces are permitted per bridge-group (inside, outside, DMZ1, DMZ2)

To let FMC manages FTD, first we need to add manager from the FTD and assign a register key of your choice. The command configure manager add 1.1.1.2 the_registration_key_you_want, where 1.1.1.2 is the IP address of the FMC, you need to use the same registration key in FMC when adding this FTD as a managed device. Reference: https://cyruslab.net/2019/09/03/ciscocisco-firepower-lab-setup/ choice. The command configure manager add 1.1.1.2 the_registration_key_you_want, where 1.1.1.2 is the IP address of the FMC, you need to use the same registration key in FMC when adding this FTD as a managed device.
To let FMC manages FTD, first we need to add manager from the FTD and assign a register key of your choice. The command configure manager add 1.1.1.2 the_registration_key_you_want, where 1.1.1.2 is the IP address of the FMC, you need to use the same registration key in FMC when adding this FTD as a managed device. Reference: https://cyruslab.net/2019/09/03/ciscocisco-firepower-lab-setup/