CCNA Practice Test - 2

With NAT overload (PAT), the router translates both the source IP and source port of internal traffic. The web server receives the packet with source IP 172.30.20.1 and source port 3333, so it sends the return packet to that same destination IP and port. The NAT table then translates it back to 10.1.1.2:1234.

IPv6 address compression rules allow replacing consecutive zeros with double colon (::), but this can only be done ONCE in an address to avoid ambiguity. Options A, B, and C incorrectly use :: twice. Option D correctly compresses the second hextet (0:0000 becomes 0) and the zero block before 9C0, using :: only once.

Fiber optic cable is immune to electromagnetic interference (EMI) and radio frequency interference (RFI) because it transmits light rather than electrical signals. It also has no electrical conductivity, eliminating shock hazards in environments with high voltage or explosive atmospheres. Copper media (coax, UTP, STP) are susceptible to EMI and can conduct hazardous voltages.

In Frame Relay, 'dynamic' refers to DLCI-to-IP address mappings learned via Inverse ARP, not statically configured. This allows routers to automatically discover which remote IP addresses correspond to which DLCIs without manual configuration. DHCP is unrelated to Frame Relay address assignment.

Router configuration modes are hierarchical: User mode (>) > Privileged mode (#) > Global config (config)# > Interface config (config-if)#. To change interface parameters like IP address, you must be in interface configuration mode, accessed via 'interface ' from global config mode.

The routing table shows routes with various subnet masks (/24, /25, /30). These are all 'network routes' because they represent specific network prefixes with their associated subnet masks. A supernet would have a shorter mask than the classful boundary (like /16 for a Class C). Parent routes appear when a more specific route exists, not when removed.

Packet-switching shares network resources among multiple subscribers. Unlike circuit-switching which dedicates a fixed path, packet-switching breaks data into packets and dynamically allocates bandwidth only during actual data transfer. This allows multiple users to share the same physical infrastructure efficiently, with resources allocated on-demand.

The key difference between IDS (Intrusion Detection System) and IPS (Intrusion Prevention System) is that IDS is passive - it only detects and alerts on attacks. IPS is inline and can actively block or prevent detected attacks from executing. This provides real-time protection rather than just notification after the fact.

The 'copy running-config startup-config' command saves the current running configuration to NVRAM so it persists across reboots. This command requires privileged EXEC mode (indicated by the # prompt), not user mode (>) or configuration modes (config)#, (config-if)#, etc. The prompt Switch-6J# indicates privileged EXEC mode.

The output shows EIGRP hello packets received from a neighbor. The key information is that router R2 (the local router) is receiving hello packets from neighbor 192.168.10.10 via interface S0/0/1. This indicates EIGRP neighbor discovery is working. The hello packets are used to form and maintain EIGRP adjacencies between routers.

FECN (Forward Explicit Congestion Notification) is the Frame Relay mechanism used to signal congestion in the forward direction. When switches detect congestion, they set the FECN bit in frames heading toward the destination to inform routers to slow down their transmission rate. BECN (Backward Explicit Congestion Notification) would signal in the reverse direction, while CIR is the committed information rate, not a signaling mechanism.

10 Gigabit Ethernet operates only over fiber-optic media.

A Cisco router enters setup mode when it cannot locate a valid configuration file in NVRAM. This happens on a new router or when the configuration register is set to ignore the startup-config. The IOS image being corrupt would cause boot failure, not setup mode. Setup mode is the router's way of getting initial configuration from the user.

In STP, the root bridge is selected based on the lowest bridge ID, which combines priority (default 32768) and MAC address. Setting a lower priority value ensures that switch becomes root. Configuring static root ports is not possible - root ports are determined by the root bridge. IP addresses have no role in STP operation, and BPDU values are not configurable.

cdp holdtime 150 specifies the amount time the receiving device should hold a CDP packet from your router before discarding it.

Cisco routers permit all IP traffic by default on all interfaces unless access lists are applied. The 'permit any any' implicit rule exists in both directions. This default behavior allows traffic to flow freely until explicitly restricted by the administrator through ACLs.

Ethernet and Token Ring MAC addresses are 6 BYTES long.

VPN over broadband provides secure, encrypted tunnels through the public internet, combining the security of traditional VPNs with the high speed and reliability of broadband connections. Users need VPN client software to establish these tunnels. This solution offers better performance than dialup while maintaining security through encryption, not plain text transmission.