CCNA Practice Test - 33

MAC address table entries expire after the aging time. If set too short, legitimate entries expire before devices finish communicating, causing the switch to flood frames to all ports because it no longer knows which port leads to the destination MAC address.

PAP uses a simple two-way handshake: the authenticator sends a challenge, and the peer responds with the username and password in plaintext. PAP is not secure as it transmits credentials unencrypted and doesn't use hashing like CHAP does.

WiMAX (Worldwide Interoperability for Microwave Access) is a broadband wireless technology designed to provide non-line-of-sight connectivity with speeds comparable to DSL. Unlike Wi-Fi which is short-range, or Satellite which has high latency, WiMAX offers metropolitan-area coverage with DSL-like speeds. Metro Ethernet requires physical cables, not a wireless solution.

Cisco Discovery Protocol (CDP) operates at Layer 2 but provides information about multiple OSI layers. The 'show cdp neighbours' command displays Layer 1 information (physical connectivity), Layer 2 information (device IDs, port IDs, capabilities), Layer 3 information (IP addresses), and Layer 4 information (OSI version info). It does not provide Layer 5-7 details.

The MAC address FF-FF-FF-FF-FF-FF represents a broadcast to all hosts in a broadcast domain.

copy tftp flash is the correct answer. copy flash tftp creates a backup from the current IOS and stores it in a file on a tftp server.

EIGRP maintains multiple databases: the routing table (best paths), neighbor table (adjacent routers), and topology table (all learned routes). Feasible successors - backup paths with loop-free guarantee - are stored specifically in the topology table. The routing table only contains the successor (best) routes, while feasible successors remain in the topology table as backup options that can be immediately promoted if the successor fails.

A routing loop occurs when packets continuously circulate between routers without reaching their destination. This typically happens due to inconsistent routing tables, slow convergence, or incorrect route redistribution. Unlike load balancing where different paths are used, a routing loop is a pathological condition that wastes bandwidth and prevents packet delivery. Option C accurately describes this condition.

When applying an ACL to an interface, Cisco IOS allows only one ACL per direction per protocol. If an inbound IP ACL is already applied and you attempt to apply another inbound IP ACL, the second ACL replaces the first - you cannot have multiple inbound ACLs on the same interface for the same protocol. This is by design to avoid conflicts and maintain predictable security policies.

When accessing a router running SDM via HTTPS, the browser presents the SDM web interface with a login dialog requesting username and password credentials. The HTTPS protocol ensures the password is encrypted during transmission (not plain text). This is not a Telnet session (which uses port 23, not 443), nor does it display a generic home page for downloading IOS files. SDM is a web-based device management tool that requires authentication.

Connectionless protocols at lower OSI layers (like IP at Layer 3 or Ethernet at Layer 2) do not provide acknowledgment or retransmission services. When data reliability is needed, upper-layer connection-oriented protocols or services (typically TCP at Layer 4) provide acknowledgments and request retransmission of missing data. IP itself is connectionless and unreliable - it relies on upper layers for reliability. The option 'connectionless acknowledgement' is contradictory because connectionless protocols don't provide acknowledgments.

When 'no network 172.16.0.0' is configured on JAX, it stops advertising 172.16.0.0/16 to ORL. However, CHI can still receive 172.16.0.0/16 from other sources and advertise it. When ORL receives 192.168.0.0/16 from JAX (after JAX receives it via distribute-list), ORL will advertise it to CHI. CHI will install this route in its routing table with a 'R' tag (RIP), not 'S' (static). The distribute-list controls what routes JAX advertises to ORL, but doesn't prevent ORL from advertising learned routes to CHI.

The 'line vty 0 4' command selects the VTY lines for remote access (Telnet/SSH). Setting 'password check123' and 'login' configures password authentication. This password is required when connecting remotely, not for user EXEC mode on the console.

Inverse ARP dynamically learns the network layer address of the remote device associated with a DLCI. This eliminates manual configuration of Frame Relay mappings. LMI is the signaling protocol, DLCI identifies virtual circuits, and FECN indicates congestion.

The frame data field (payload) carries the encapsulated network layer PDU (packet). Physical addressing (MAC addresses) goes in the header, not data field. FCS (Frame Check Sequence) is a trailer field. SOF (Start of Frame) and preamble are preamble fields.

The 'ip dhcp excluded-address' command tells the DHCP server to exclude a range of addresses from being assigned to clients. This is typically done for servers, printers, or router interfaces that need static IP addresses. It does not affect traffic routing or dropping.