ASA MODE
TRANSPARENT MODE
A transparent firewall is a Layer 2 firewall.
Both the interfaces of ASA is in same subnet. We can easily
introduce firewall in the network.
Traffic for IPV4 and
IPV6 are allowed form higher security interface to lower security interface
without access list.

Inside interface is configure for higher
security level and outside interface configure for lower security level.
Traffic from inside interface to outside interface will flow
without configuring access list.
To allow traffic from outside interface to inside interface
we need to configure access list.
The following destination mac addresses are allowed
0100.5E00.0000 to 0100.5EFE.FFFF IPV4 multicast addresses
3333.0000.0000 to 3333.FFFF.FFFF IPV6
multicast addresses
0100.0CCC.CCCD BPDU mac address
CDP packets are blocked in transparent firewall.
Routed MODE
In Routed mode, ASA acts as a router between interfaces.Routed mode supports many interfaces. All interfaces of ASA will be in different subnet. All interfaces will be having ip address belonging to seperate subnet.
For example,ASA has two interface (inside and outside). Both interfaces will belong to different subnet. Both interface has differnet security level. Inside has higher security level and outside interface has lower security level.
Network connected to interface will use ip address of that interface as a default gateway
