Cisco CCNA Practice Test 4 — Questions and Answers
Question 1: What is the maximum number of usable host addresses in a /28 subnet?
- 14 (Correct answer)
- 16
- 30
- 62
Correct answer: 14
A /28 subnet has 16 total addresses (2^4), with 14 usable host addresses after subtracting network and broadcast.
Question 2: Which Cisco IOS command saves the running configuration to NVRAM?
- copy startup-config running-config
- write memory (Correct answer)
- save configuration
- copy running-config flash
Correct answer: write memory
The 'write memory' command (or its equivalent 'copy running-config startup-config') saves the current configuration to NVRAM.
Question 3: Which field in an IP packet header is decremented by one at each router hop?
- TOS
- Protocol
- TTL (Correct answer)
- Checksum
Correct answer: TTL
The Time to Live (TTL) field is decremented by 1 at each router hop; when it reaches 0, the packet is discarded.
Question 4: What is the purpose of the Cisco Discovery Protocol (CDP)?
- To encrypt management traffic between Cisco devices
- To discover directly connected Cisco devices and their capabilities (Correct answer)
- To synchronize clocks across Cisco devices
- To distribute VLAN information across a network
Correct answer: To discover directly connected Cisco devices and their capabilities
CDP is a Cisco proprietary Layer 2 protocol that allows Cisco devices to discover and share information about directly connected neighbors.
Question 5: Which type of NAT maps one private IP address to one public IP address?
- Dynamic NAT
- NAT overload
- Static NAT (Correct answer)
- PAT
Correct answer: Static NAT
Static NAT creates a permanent one-to-one mapping between a private IP address and a public IP address.
Question 6: Which STP variant is defined by IEEE 802.1w and provides faster convergence than 802.1D?
- PVST+
- RSTP (Correct answer)
- MSTP
- VSTP
Correct answer: RSTP
Rapid Spanning Tree Protocol (RSTP), defined in IEEE 802.1w, significantly reduces convergence time compared to the original STP.
Question 7: A host with IP 172.16.5.10/20 needs to communicate with 172.16.14.20. Are these hosts on the same subnet?
- Yes, both are in the 172.16.0.0/20 network (Correct answer)
- No, they are in different /20 subnets
- Yes, both are in the 172.16.4.0/20 network
- Cannot be determined without the default gateway
Correct answer: Yes, both are in the 172.16.0.0/20 network
A /20 mask covers 172.16.0.0–172.16.15.255; both .5.10 and .14.20 fall within that range, so they are on the same subnet.
Cisco CCNA Practice Test 4
What is the maximum number of usable host addresses in a /28 subnet?