CCNA Network Security Devices Questions

An inline IPS must keep up with line rate; otherwise it will drop legitimate packets or introduce unacceptable latency. Sizing and tuning the inspection engine for the full 10 Gbps plus expected bursts ensures the device does not become a performance bottleneck or a de facto denial of service. This directly supports the goal of maintaining availability while enforcing prevention. It is a fundamental capacity planning requirement for inline IPS on critical high-speed links.

VLANs logically separate the guest and internal broadcast domains, and an ACL on the router interface enforces policy between them. Because inter-VLAN traffic must be routed, the router is the correct enforcement point. This combination directly prevents guest users from reaching internal file servers while still allowing both groups to reach the internet through controlled paths. It is the standard and effective way to segment a flat network with existing Layer 2 and Layer 3 equipment.

SPAN copies frames from selected switch ports or VLANs to a monitoring port, giving passive visibility of east-west traffic without inline interception. This satisfies the constraint of capturing raw packets while production flows continue uninterrupted.

Application-aware filtering with DPI examines packet payloads beyond headers to identify applications regardless of port or protocol. It can detect tunneling and evasive techniques by analyzing behavioral patterns and signatures. This directly addresses the requirement to enforce policies based on application identity and to handle non-standard ports and HTTP tunneling.

A stateful firewall maintains a connection table and permits return traffic for sessions that were initiated according to policy. Many stateful firewalls also perform network address translation at the edge. The scenario describes stateful connection tracking and NAT but not deep application inspection, which is exactly the core behavior of a traditional stateful firewall. This device type fits the placement and described functions precisely.

Stateful inspection maintains a session table that tracks the state of each connection. When an outbound connection is initiated, the firewall creates an entry, and return traffic matching that session is automatically allowed. If session tracking is disabled or the table is full, return packets may be dropped. This feature is essential for allowing return traffic without explicit inbound rules.

Deep packet inspection that understands Modbus/TCP can parse the function code field and enforce an allowlist of approved read operations while dropping others, which matches the requirement to block unauthorized function codes. Because it is purpose-built for OT protocols, it can do this without the latency and compatibility problems a general-purpose proxy would introduce.

For an inline IPS on a high-speed clinical link, the device must handle 10 Gbps of traffic without adding latency that affects real-time monitoring. A hardware bypass or fail-to-wire capability ensures that if the IPS fails or loses power, traffic continues to flow, preserving patient safety. This combination of performance and availability is the primary deployment consideration for this scenario.

The router processes the ACL in a top-down fashion. The first rule denies all traffic to 10.0.5.5 on port 80. Since the packet matches this criteria, the evaluation stops, and the router silently discards the packet. The permit rule located on the second line is never reached.

Passive IDS sensors monitor mirrored traffic without interfering with packet delivery. Upon detecting malicious indicators, they record the event to local logs and transmit alerts to centralized management systems and SIEM platforms for analyst review.

To inspect TLS 1.3 payloads, the WAF must be a TLS endpoint, which means presenting a certificate and possessing the corresponding private key so it can decrypt, examine, and re-encrypt sessions. Without this termination capability the WAF only sees ciphertext and cannot evaluate HTTP request content, making it useless against application-layer attacks on the portal.

Overload often comes from inspecting irrelevant protocols and signatures, which consumes CPU and causes legitimate packets to be dropped. Profiling the segment and disabling unused signatures reduces processing load without removing inline prevention. This preserves enforcement while lowering false positives and false drops. It is the targeted, operationally sound adjustment because it aligns inspection scope with actual traffic rather than disabling protection.

Reverse proxy mode places the WAF inline for HTTP/HTTPS traffic, and anomaly detection with a learning period builds a behavioral baseline of legitimate requests. After the baseline is established, deviations from normal parameters, methods, and request patterns can be blocked without hand-written signatures. This directly matches the architect's requirement to learn normal behavior and block deviations, while reverse proxy mode gives the WAF full visibility and control over application traffic.

Stateful firewalls age out entries in the session table based on idle timers, and the default TCP idle timeout is often around an hour for established connections. If the SSH session carries no keepalive traffic during that window, the entry is purged and subsequent packets are treated as a new, unauthorized flow and dropped, matching the observed hourly disconnects.

A UTM appliance integrates several security services, such as antivirus, content filtering, intrusion prevention, and often VPN, into one device that traffic traverses. This consolidation is exactly what the owner wants: a single platform applying multiple inspection technologies to outbound flows without deploying separate dedicated appliances.

An inline Layer 2 bridge inspects traffic between the two VLANs while remaining transparent to IP addressing, and a hardware bypass fail-to-wire segment physically shunts packets around the appliance if it loses power, preserving connectivity for clinical systems. This directly satisfies both the inspection and the survivability requirements without renumbering hosts or altering routing.