An organization has a Cisco FTD that uses bridge groups to pass traffic from the inside interfaces to the outside interfaces. They are unable to gather information about neighbouring Cisco devices…

Question

Options

• ACreate a firewall rule to allow CDP traffic.
• BCreate a bridge group with the firewall interfaces.
• CChange the firewall mode to transparent.
• DChange the firewall mode to routed.

• A
  5% (2)
• B
  2% (1)
• C
  84% (37)
• D
  9% (4)

Explanation

Cisco FTD in routed mode with bridge groups does not support Layer 2 protocols such as CDP (Cisco Discovery Protocol) or multicast traffic between bridge group interfaces, because routed mode processes traffic at Layer 3. Transparent mode makes the FTD behave as a 'bump in the wire' (Layer 2 device), passing Layer 2 frames-including CDP advertisements and multicast packets-directly between interfaces in the same bridge group without stripping or blocking them. Switching to transparent mode allows neighboring Cisco devices to exchange CDP information and enables multicast to traverse the firewall. Option A is incorrect because CDP is a Layer 2 protocol and cannot be permitted by a Layer 3 ACL/firewall rule. Option B describes a configuration that already exists. Option D (routed mode) is the current cause of the problem, not the fix.

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