CSLB General Building (B) — All Questions

What does the acronym 'IP' stand for in networking?

• a.Internal Protocol
• b.Interface Port
• c.Internet Protocol✓
• d.Integrated Packet

IP stands for Internet Protocol, which is responsible for addressing and routing packets of data so they can travel across networks. Every device on an IP network has an IP address. IP works together with TCP in the widely used TCP/IP suite.

What is the primary purpose of DNS (Domain Name System)?

• a.To translate human-readable domain names into IP addresses✓
• b.To assign IP addresses automatically to devices
• c.To encrypt web traffic
• d.To physically connect cables between routers

DNS acts like the internet's phone book, translating domain names such as example.com into the numeric IP addresses computers use to communicate. Without DNS, users would need to memorize IP addresses. DNS resolution happens through a hierarchy of servers.

What does DHCP do on a network?

• a.Encrypts all network traffic
• b.Automatically assigns IP addresses and network configuration to devices✓
• c.Translates domain names to IP addresses
• d.Blocks malicious websites

DHCP (Dynamic Host Configuration Protocol) automatically assigns IP addresses, subnet masks, gateways, and DNS servers to devices as they join a network. This removes the need to configure each device manually. Addresses are leased for a period and can be renewed.

Which protocol is connection-oriented and ensures reliable, ordered delivery of data?

• a.ICMP
• b.UDP
• c.ARP
• d.TCP✓

TCP (Transmission Control Protocol) establishes a connection and guarantees that data arrives reliably and in order, retransmitting lost packets. This makes it suitable for applications like web browsing and email. UDP, by contrast, is faster but does not guarantee delivery.

How many layers are in the OSI networking model?

• a.Seven✓
• b.Four
• c.Five
• d.Nine

The OSI (Open Systems Interconnection) model has seven layers: physical, data link, network, transport, session, presentation, and application. Each layer has a specific role in network communication. The model is a conceptual framework used to understand and troubleshoot networks.

What is a MAC address?

• a.A temporary address assigned by DHCP
• b.The name of a website
• c.A unique hardware identifier assigned to a network interface✓
• d.A type of encryption key

A MAC (Media Access Control) address is a unique identifier burned into a network interface card by the manufacturer. It operates at the data link layer and is used for communication within a local network segment. Unlike IP addresses, MAC addresses are generally fixed to the hardware.

What is the role of a router in a network?

• a.To store website data
• b.To forward data packets between different networks✓
• c.To generate electricity for devices
• d.To scan for viruses

A router directs data packets between separate networks, such as between a home network and the internet. It determines the best path for traffic based on IP addresses and routing tables. Routers are essential for connecting local networks to the wider internet.

What does a subnet mask define?

• a.The speed of the network
• b.The physical length of a cable
• c.The color coding of network wires
• d.Which portion of an IP address identifies the network versus the host✓

A subnet mask divides an IP address into a network portion and a host portion. This lets devices determine whether a destination is on the local network or needs to be routed elsewhere. For example, 255.255.255.0 designates the first three octets as the network.

Which command is commonly used to test connectivity to another host by sending echo requests?

• a.ping✓
• b.format
• c.chmod
• d.del

The ping command sends ICMP echo request packets to a target host and reports whether replies are received and how long they take. It is a fundamental tool for testing basic network connectivity. A successful ping indicates the host is reachable.

What is the difference between TCP and UDP?

• a.TCP is wireless while UDP is wired
• b.TCP is for video only while UDP is for text only
• c.TCP is reliable and connection-oriented while UDP is faster but connectionless✓
• d.There is no difference between them

TCP establishes a connection and guarantees reliable, ordered delivery with error checking and retransmission. UDP is connectionless and does not guarantee delivery, trading reliability for lower overhead and speed. UDP suits real-time uses like streaming and online gaming.

Which port number is the default for HTTP web traffic?

• a.443
• b.80✓
• c.22
• d.53

HTTP typically uses port 80 for unencrypted web traffic. Port 443 is used for HTTPS, the encrypted version. Knowing common port numbers helps in configuring firewalls and troubleshooting connectivity.

What does the 'traceroute' (or tracert) command show?

• a.The MAC address of a device
• b.The amount of free disk space
• c.The password of a router
• d.The path packets take through routers to reach a destination✓

Traceroute maps the route packets take from your computer to a destination, listing each hop along the way and the time to reach it. This helps identify where delays or failures occur in the path. On Windows the command is tracert.

What is NAT (Network Address Translation) used for?

• a.Allowing multiple devices on a private network to share a single public IP address✓
• b.Encrypting all email messages
• c.Speeding up the CPU
• d.Translating domain names to IP addresses

NAT lets many devices on a private network share one public IP address when accessing the internet. The router translates private addresses to the public address and tracks connections. This conserves scarce public IPv4 addresses and adds a layer of separation.

What is the main difference between IPv4 and IPv6?

• a.IPv6 is only for wireless networks
• b.IPv6 uses 128-bit addresses providing far more available addresses than IPv4's 32-bit✓
• c.IPv4 is newer than IPv6
• d.IPv6 does not use IP addresses

IPv4 uses 32-bit addresses, allowing about 4.3 billion unique addresses, which are running out. IPv6 uses 128-bit addresses, providing a vastly larger address space. IPv6 was developed to address IPv4 exhaustion and includes other improvements.

What device connects multiple devices within a single local network and forwards frames based on MAC addresses?

• a.A modem
• b.A router
• c.A switch✓
• d.A firewall

A switch connects devices within the same local network and uses MAC addresses to forward frames only to the intended port. This makes it more efficient than an older hub, which broadcast to all ports. Switches operate primarily at the data link layer.

What does 'bandwidth' refer to in networking?

• a.The maximum rate of data transfer across a network connection✓
• b.The physical thickness of a cable
• c.The number of devices on a network
• d.The distance between two routers

Bandwidth is the maximum amount of data that can be transferred over a network connection in a given time, often measured in megabits per second. Higher bandwidth generally allows more data to move faster. It should not be confused with latency, which is delay.

Which protocol securely encrypts web traffic and is indicated by 'https' in a URL?

• a.FTP
• b.Telnet
• c.SMTP
• d.TLS/SSL (HTTPS)✓

HTTPS uses TLS (formerly SSL) to encrypt data between a browser and a web server. This protects information like passwords and payment details from eavesdropping. A padlock icon in the browser usually indicates a secure HTTPS connection.

What is 'latency' in a network?

• a.The total storage capacity of a server
• b.The delay between sending and receiving data✓
• c.The number of open ports
• d.The encryption strength of a connection

Latency is the time it takes for data to travel from source to destination, usually measured in milliseconds. High latency causes noticeable delays, which is especially problematic for video calls and gaming. It is distinct from bandwidth, which measures capacity.

What is the purpose of a default gateway on a device?

• a.To store DNS records
• b.To encrypt the local network
• c.To provide the route for traffic destined outside the local network✓
• d.To assign MAC addresses

The default gateway is the device, usually a router, that traffic is sent to when the destination is not on the local network. It acts as the exit point toward other networks and the internet. Without a correct gateway, a device cannot reach external networks.

Which command displays a computer's IP configuration on Windows?

• a.ipconfig✓
• b.ls
• c.chmod
• d.ping google

The ipconfig command on Windows displays the current IP address, subnet mask, and default gateway for the machine's interfaces. Using ipconfig /all reveals more details like DNS servers and the MAC address. On Linux and macOS, ip addr or ifconfig serves a similar role.