Chapter 10: Data Communication and Internet Services (Set-2)
When a message is broken into smaller units for transmission across networks, those units are called
A Domain records
B Session cookies
C Port numbers
D Data packets
Networks send large data by splitting it into packets. Each packet carries a header for addressing and ordering, so routers can forward them and the receiver can reassemble correctly.
Which term best describes unwanted changes to a signal caused by interference during transmission
A Static address
B Noise interference
C Link protocol
D Host caching
Noise is any unwanted disturbance that distorts a signal while traveling through a medium. It can cause bit errors, reduce quality, and force retransmissions, lowering overall network performance.
In digital communication, which effect refers to reduced signal strength over distance in a cable
A Packet loss
B Name resolution
C Signal attenuation
D Port scanning
Attenuation means the signal becomes weaker as it travels. Long cables or poor-quality media increase attenuation, so repeaters, amplifiers, or better media are used to maintain reliability.
In basic communication terminology, the “message” refers to
A Physical cable
B Data being sent
C Routing device
D Network interface
The message is the actual information transferred from sender to receiver, such as text, audio, or a file. It is carried over a medium using protocols for correct delivery.
Which OSI layer is responsible for converting data into signals and sending bits on the wire or air
A Physical layer
B Network layer
C Session layer
D Application layer
The Physical layer handles the transmission of raw bits as electrical, optical, or radio signals. It defines signal levels, connectors, timing, and the physical characteristics of the link.
Which OSI layer handles data formatting, encryption, and compression for applications
A Transport layer
B Data Link layer
C Physical layer
D Presentation layer
The Presentation layer ensures data is in a readable format for the Application layer. It may handle character encoding, encryption/decryption, and compression so different systems interpret data correctly.
Which OSI layer manages dialog control, checkpoints, and session establishment between systems
A Network layer
B Session layer
C Physical layer
D Data Link layer
The Session layer creates, manages, and ends communication sessions between devices. It can support synchronization and recovery using checkpoints, helpful when long data transfers need restart points.
In the TCP/IP model, IP works mainly at the
A Application layer
B Link layer
C Internet layer
D Presentation layer
In TCP/IP, IP is part of the Internet layer and provides logical addressing and routing. It moves packets across multiple networks using routers to reach the destination IP.
Which protocol is commonly used to automatically assign DNS server details to a new device on a LAN
A HTTP protocol
B DHCP protocol
C FTP protocol
D SMTP protocol
DHCP can provide a device with an IP address plus settings like DNS server, subnet mask, and default gateway. This allows a device to connect and resolve names without manual setup.
A DNS “record” is best described as
A Port access rule
B Encryption key file
C Upload permission
D Stored mapping entry
DNS records store information in DNS servers, such as name-to-IP mappings and mail routing. Common records include A/AAAA for addresses and MX for mail delivery instructions.
Which DNS record type is mainly used to specify the mail server for a domain
A A record
B PTR record
C MX record
D TXT record
An MX record tells other mail servers which server receives email for a domain. It supports priority values so mail can be delivered to backup servers if the primary fails.
Which DNS record is commonly used for IPv4 address mapping of a host name
A MX record
B A record
C SRV record
D PTR record
An A record maps a domain or host name to an IPv4 address. When a browser looks up a website name, DNS often returns the IP using A (or AAAA for IPv6).
DNS reverse lookup (IP to name) typically uses
A PTR record
B MX record
C CNAME record
D TXT record
A PTR record maps an IP address back to a host name, used for reverse DNS lookups. It is often checked by email systems to reduce spoofing and improve trust.
A CNAME record mainly provides
A IP lease timing
B Port forwarding rule
C Alias name mapping
D Packet encryption
CNAME creates an alias from one name to another canonical name. It helps point multiple hostnames to a single primary name without repeating the same A/AAAA records.
Which idea best matches “DNS resolver caching”
A Encrypting all queries
B Reusing recent answers
C Converting MAC to IP
D Blocking all domains
Resolvers store previous DNS results for a set time (TTL). Reusing cached answers reduces DNS traffic and speeds up repeated visits to the same websites.
DHCP “lease renewal” means the device
A Changes DNS zone
B Closes TCP session
C Resets MAC address
D Extends its lease
Before a lease expires, a device requests renewal from the DHCP server. If approved, the same IP can remain assigned, helping avoid address changes and connectivity interruptions.
In DHCP, which component usually hands out IP settings to clients
A DNS server
B Web browser
C DHCP server
D FTP client
The DHCP server manages a pool of addresses and configuration options. It responds to client requests by assigning an IP address and related network settings automatically.
In a URL, the part “https” mainly indicates
A Host name
B Protocol scheme
C File extension
D DNS record
The scheme tells the browser which protocol to use. “https” means the browser should use HTTP over TLS encryption, improving confidentiality and integrity compared to plain HTTP.
Which part of a URL typically identifies the server domain
A Host name
B Query string
C Fragment tag
D Cookie value
The host name is the domain or server name in a URL, such as example.com. DNS resolves this name into an IP address so the browser can connect to the correct server.
In HTTP, the request/response model means
A Server always pushes data
B DNS returns web pages
C Client asks, server replies
D Router stores cookies
In HTTP, a client sends a request for a resource and the server responds with status and data. This pattern is the basis of web browsing and many web APIs.
Which HTTP status code indicates “success” for a normal request
A 404 Not Found
B 200 OK
C 500 Error
D 403 Forbidden
HTTP 200 means the server successfully processed the request and returned the resource. Browsers use this to display pages when the requested content is available normally.
Which HTTP status code indicates the client is not allowed to access the resource
A 201 Created
B 301 Redirect
C 200 OK
D 403 Forbidden
403 means the server understood the request but refuses to authorize it. This often happens due to missing permissions, blocked access rules, or restricted content.
Which HTTP status code often indicates a server-side problem
A 302 Redirect
B 404 Not Found
C 500 Error
D 204 No Content
500 indicates an internal server error. The server failed to complete the request due to a problem in server software, configuration, or temporary overload.
A “redirect” in web browsing generally means
A Faster bandwidth
B New URL location
C Extra DNS caching
D Lower packet size
A redirect instructs the browser to load a different URL. It is used when pages move, when HTTP upgrades to HTTPS, or when websites route users to correct paths.
Web certificates mainly help by
A Proving server identity
B Increasing file size
C Blocking DHCP leases
D Changing MAC address
Digital certificates support HTTPS by proving the server’s identity to the browser and enabling encrypted communication. They are issued by trusted certificate authorities to reduce impersonation risk.
TLS is best described as
A Routing table entry
B DNS zone file
C Encryption security protocol
D Address lease timer
TLS secures data in transit by providing encryption and integrity checks. It is used in HTTPS and other secure connections, reducing risks like eavesdropping and data tampering.
FTP “authentication” usually requires
A Only IP address
B Username and password
C Only MAC address
D Only port number
FTP typically uses a login system to control access. Users provide credentials so the server can allow uploading, downloading, and directory access based on assigned permissions.
Anonymous FTP usually means login with
A Encrypted certificate only
B Random MAC address
C Fixed static gateway
D Common public credentials
Anonymous FTP allows public access without personal accounts. Users often log in with “anonymous” and provide an email-like password, depending on server settings, to download public files.
FTP “upload” means
A Client receives file
B DNS returns IP
C Client sends file
D Router forwards packets
Uploading in FTP means transferring a file from the client machine to the FTP server. Downloading is the opposite direction, from server to client.
FTP “download” means
A Client sends file
B Client receives file
C DHCP assigns IP
D TLS encrypts data
Downloading in FTP means the client retrieves a file from the server to the local system. It is commonly used to obtain software packages or website backups.
The key idea of “ports” in networking is
A Service identification numbers
B Cable connector shapes
C Wi-Fi channel names
D DNS server records
Ports are logical numbers used with IP addresses to identify which application or service should receive the traffic. For example, web and email use different port numbers.
POP3 is mainly used to
A Send outgoing mail
B Assign IP addresses
C Transfer web pages
D Download email
POP3 lets an email client retrieve messages from a mail server, often storing them locally. It is simpler than IMAP and is commonly used for basic email downloading.
IMAP is mainly used to
A Encrypt web traffic
B Resolve domain names
C Sync mailbox
D Share one IP
IMAP keeps email on the server and synchronizes folders across devices. This makes it easy to access the same mailbox from phone, laptop, and webmail consistently.
SMTP is mainly used for
A Receiving email
B Sending email
C Assigning IP lease
D Loading web pages
SMTP is used to send email from clients to servers and between mail servers. It handles outgoing mail delivery, while POP3/IMAP typically handle reading or syncing messages.
A proxy server is often used to
A Generate MAC addresses
B Replace subnet mask
C Increase attenuation
D Forward client requests
A proxy acts as an intermediary between users and the internet. It can filter traffic, provide caching, improve privacy, or enforce access policies in organizations.
A VPN mainly provides
A Faster DNS records
B Encrypted network tunnel
C Automatic port scanning
D Static MAC masking
A VPN creates an encrypted tunnel between your device and a VPN server, protecting data over untrusted networks and often allowing secure access to private networks or remote resources.
NAT is commonly used in routers to
A Store cookies locally
B Create DNS zones
C Translate private addresses
D Encrypt FTP sessions
NAT translates private IP addresses used inside a home or office into a public IP for internet access. This allows multiple devices to share one public address and conserves IPv4 space.
A MAC address is best described as
A Web page address
B IP lease duration
C DNS server name
D Hardware network identifier
A MAC address is a unique identifier assigned to a network interface card. It is used mainly at the Data Link layer for local network communication within the same LAN segment.
An ISP primarily provides
A DNS record editing
B Internet connection service
C CPU upgrade support
D Local file encryption
An ISP connects users to the internet using fiber, cable, DSL, or mobile networks. Many ISPs also provide services like DNS, email, and basic hosting or router support.
Web hosting means providing
A VPN encryption keys
B DHCP address pool
C Server space for site
D DNS cache memory
Web hosting provides server storage and resources so a website’s files can be stored and accessed online. Hosting includes uptime, bandwidth, and web server software to serve pages.
VoIP is best described as
A Voice over internet
B File transfer method
C DNS security tool
D IP lease protocol
VoIP carries voice calls using internet data packets instead of traditional telephone circuits. It requires stable connectivity and often uses compression and real-time transport techniques to reduce delay.
The main purpose of “ping” results is to show
A DNS record priority
B Reachability and delay
C FTP login status
D HTTPS certificate type
Ping indicates whether a host responds and measures round-trip time. Consistent high times or timeouts can suggest congestion, routing issues, or blocking by firewalls.
Traceroute is useful when you want to
A Create new domain name
B Encrypt HTTP traffic
C Assign static IP
D Locate slow network hop
Traceroute lists the routers (hops) between your device and a destination. It helps identify where delays, packet loss, or failures occur along the route.
A “data packet header” commonly contains
A Only file content
B Only encryption key
C Addressing and control
D Only cookie data
Packet headers carry information like source/destination addresses, sequencing, and protocol details. Routers read headers to forward packets correctly, while receivers use them to reassemble and verify data.
Which is a common reason for using caching in web and DNS systems
A Faster repeated access
B Slower browsing speed
C More signal noise
D Higher attenuation
Caching stores previously fetched results (like DNS answers or web content). Reusing cached data reduces repeated network requests, saves bandwidth, and improves speed for users accessing the same resources again.
In networking, “protocol suite” means
A Single cable standard
B Related protocol collection
C Router password list
D One DNS record
A protocol suite is a group of related protocols that work together. For example, TCP/IP includes IP, TCP, UDP, and many application protocols like HTTP, DNS, and SMTP.
The main role of UDP in many apps is
A Guaranteed ordering
B Mandatory encryption
C Domain name mapping
D Low-overhead delivery
UDP avoids connection setup and heavy reliability features, making it lightweight. It suits voice, video, and fast queries where small losses are acceptable or managed by the application.
The main role of TCP “acknowledgment” is to
A Assign IP to client
B Resolve domain name
C Confirm data received
D Open VPN tunnel
TCP uses acknowledgments to confirm packets arrived. If acknowledgments are missing, TCP retransmits, helping ensure reliable delivery and correct ordering for applications like web browsing and file transfers.
In HTTP, “cookies vs sessions” commonly means
A DNS cache vs DNS zone
B Browser token vs server state
C IP route vs MAC route
D Port number vs subnet
Cookies store small identifiers in the browser, while sessions usually store user state on the server. A session ID cookie links the browser to server-side session data for logins and tracking.
The basic purpose of DHCP “dynamic IP” is
A Automatic address assignment
B Permanent fixed address
C Encrypted web browsing
D Email delivery routing
Dynamic IP means the device receives an address automatically from DHCP and it may change over time. This reduces manual setup, prevents conflicts, and simplifies connecting many devices on a network.