Network-Security-Essentials Exam Dumps - Network Security Essentials for Locally-Managed Fireboxes

Comprehensive Technical Explanation:

A standard Class C or /24 subnet mask (255.255.255.0) allocates 24 bits for the network identifier and leaves 8 bits for the host field, yielding a total of 2^8 = 256 total IPv4 addresses. Within any standard IPv4 subnet, two specific addresses are mathematically reserved and cannot be assigned to an individual host interface: the network identifier, where all host bits are binary zeros (10.0.1.0), and the network directed broadcast address, where all host bits are binary ones (10.0.1.255). Consequently, the usable host address range for the 10.0.1.0/24 subnet spans from 10.0.1.1 through 10.0.1.254. Option C (10.0.1.100/24) resides within this usable host address range and represents a valid static or DHCP host assignment. Option E (10.0.1.0) is invalid because it is the base network ID. Option B (10.0.1.255) is invalid because it is the broadcast address. Options A (10.0.10.24) and D (10.0.0.1) belong to entirely different subnets (10.0.10.0/24 and 10.0.0.0/24, respectively).

Comprehensive Technical Explanation:

Under 802.1Q VLAN encapsulation standards, an Ethernet interface can send and receive frames that carry a 4-byte 802.1Q VLAN tag (tagged) or carry no tag header (untagged). When connecting a Firebox interface to an intermediate managed network switch over an 802.1Q trunk link carrying multiple virtual networks, the interface configuration on the Firebox must match the trunk configuration on the switch port.

The topology diagram shows the physical link between the Firebox and the switch carrying:

- VLAN 10 Tagged

- VLAN 20 Tagged

Because the switch forwards frames for both VLAN 10 and VLAN 20 across that uplink with IEEE 802.1Q headers intact, the Firebox physical interface must be configured as a member of VLAN 10 (Tagged) and VLAN 20 (Tagged). This ensures the Fireware network driver processes 802.1Q tags, demultiplexes incoming frames to their respective virtual VLAN sub-interfaces (vlan10 and vlan20), and tags outbound return traffic appropriately.