150 Questions
Which log file contains information and error messages generated by the cron and at daemons?
cron
Which package manager is associated with the rpm command?
Red Hat Package Manager
Which log file provides detailed information regarding daemon startup and system messages?
syslog
Which log file contains a history of all login sessions?
wtmp
Which log file contains information and error messages generated by X Windows?
XFree86
Which log file provides basic information regarding daemon startup obtained during system initialization?
boot.log
What command in Linux allows a user to switch to the root user if allowed by the distribution?
su Command (Switch User or Super User or Substitute User)
In Windows 10, which tab in Task Manager shows currently running processes and resource utilization?
Process Tab
What does the sudo command in Linux prefix to any command that requires administrative rights?
Super User Do
Which command is used in Linux to mount a vfat file system on a specific device to a specific directory?
sudo mount -t vfat /dev/sdc1 /media/usb
What type of commands in Linux require superuser (administrator or root user) privileges?
sudo commands
In Windows 10 Task Manager, how are running processes sorted in the Process Tab?
Alphabetically
Which command is used to attach a file system to a directory in Linux?
mount
What is the purpose of the /etc/fstab file in Linux?
To create mount entries for other storage devices for automatic mounting
Which command is used to determine the device to mount in Linux?
fdisk -l
What type of links create multiple copies of the same file linked together in Linux?
Hard links
Which file contains environment variable settings and programs executed when a user logs in?
/etc/profile
What is the purpose of the mount command in Linux?
To attach a file system to a directory
What does the top command display?
Real-time system statistics with a 5-second delay
Which directory in Linux contains system executables?
/sbin
What does the vmstat command report on?
All of the above
Which tool in Linux tracks hardware and software problems and changes to the system?
Automatic Bug Reporting Tool (ABRT)
What does the uptime command display?
All of the above
What does the /proc directory in Linux provide?
Runtime system information
Which tool in Windows Task Manager allows users to view and manage system programs running in the background?
Services tab
What does the ps command in Linux do?
Lists all processes running on the system
What can be changed in the App History tab in Windows Task Manager?
History for all processes can be shown
What does the kill command in Linux do with the option 'kill -9 PID'?
Stops a process
What does the GNOME System Monitor's Processes tab provide options for?
Controlling displayed processes and view dependencies
What can Performance Monitor in Windows 10 be used for?
Collecting and viewing real-time data about a system's usage activities
What are the respective port numbers for SNMP and RDP protocols in TCP/IP networking?
SNMP: 161, RDP: 3389
What is the purpose of APIPA in TCP/IP networking?
To automatically assign IP addresses to systems when DHCP is not available
What is the function of the Transport layer in the TCP/IP model?
To provide end-to-end communication between applications
Which protocol is commonly used for secure file transfer in TCP/IP networking?
SSH (Secure Shell)
What is the primary function of DNS in TCP/IP networking?
To translate domain names to IP addresses
Which TCP/IP protocol is commonly used for sending and receiving email?
SMTP (Simple Mail Transfer Protocol)
What is the purpose of the Network Interface layer in the TCP/IP model?
To transmit data over the physical network medium
What is the purpose of a MAC address on a local area network (LAN)?
To uniquely identify a computer on the network
Which layer of the OSI Reference Model is responsible for transporting application layer payloads using TCP for guaranteed delivery and UDP for fast transmission?
Transport Layer
What is the purpose of IP addresses in network communication?
To find computers on the Internet and local networks
Which layer of the OSI Reference Model interfaces with the physical hardware on the local network and uses MAC addresses for transmitting data?
Data Link Layer
What type of network connections can be used for homes and offices?
Wireless (Wi-Fi, satellite, cellular)
What is the purpose of port numbers in network communication?
To uniquely identify the type of application on a computer
What is the responsibility of the Network Layer in the OSI Reference Model?
To move messages from one node to another using IP protocol and routing protocols
Which suite of protocols is commonly used for almost all networks today, including the Internet?
TCP/IP (Transmission Control Protocol/Internet Protocol)
In a client/server model, which computer takes on the role of making requests from the other computer?
The client computer
At which level does the network communication start with an application passing a request to the OS, which then passes the request to the network card and on to the network?
Application Level
What is the primary function of the hardware level in network communication?
Consists of a network card and connection to the network
In the context of networking communication, what are the three basic steps in communication?
One computer finding the other, agreeing on communication methods and rules, and making requests
Which model involves two computers making requests from each other, such as two computers on a home network sharing files?
Peer-to-peer model
What must two devices use in order to communicate effectively in network communication?
The same protocols
What type of address specifies a single node on a network in IPv6?
Link local address
What type of address in IPv6 can identify multiple destinations, with packets delivered to the closest destination?
Anycast address
What is the purpose of a fully qualified domain name (FQDN) in networking?
Identifies a computer and the network to which it belongs
Which protocol is used by a DNS server to find an IP address for a computer when the fully qualified domain name is known?
DNS
What is the subnet ID in IPv6 used for?
Identifies a subnet
What does the DNS Client do when it tries to resolve a computer name to an IP address?
Looks in the DNS cache stored in memory
What does the first 64 bits of a link local address in IPv6 always start with?
fe80:0000:0000:0000 (in hex)
What is the purpose of a unique local address in IPv6?
Is a private address that can travel across subnets within the private network
What does the character-based name 'Host Name' represent in networking?
The name of a computer and can be used in place of its IP address
What technology is commonly used for a PAN to communicate at close range?
Bluetooth
In which type of network are workstations, servers, printers, and other devices used to communicate and share resources?
LAN
What technology is commonly used in a MAN to cover a large campus or city?
Ethernet over fiber optic cable
Which type of network covers a large area and is made up of many smaller networks, like the Internet?
WAN
What technology is commonly used for a WLAN where network cabling is inconvenient to install or use?
Wi-Fi
What does a LAN cover?
Small local area
What is a characteristic of a PAN?
Consists of personal devices communicating at close range
What is a characteristic of a MAN?
Covers large campus or city
What is a characteristic of a WLAN?
Uses wireless connections where network cabling is inconvenient
What is a characteristic of a WAN?
Covers a large area made up of many smaller networks
Which technology is used for providing fault tolerant data storage in a separate standalone device on a local area network?
NAS
Which RAID level provides fault tolerance but no performance increase?
RAID Level 1
Which storage technology is the server equivalent of SATA but with more capabilities?
SAS
Which protocol is used for fast transmissions over LANs, WANs, and the Internet mainly for storage on a SAN?
iSCSI
What is the purpose of a UPS (Uninterruptible Power Supply) in networking and server hardware?
To serve as a battery backup during blackouts
What is the function of redundant hardware in networking and server hardware?
To provide fault tolerance
Which protocol is commonly used for almost all networks today, including the Internet?
TCP
What is the primary role of Fiber Channel (FC) in networking?
To provide fault tolerance for data storage
What is the purpose of iSCSI (Internet SCSI) in networking?
To provide fault tolerance for data storage
What is the function of Tape Drives in networking and server hardware?
To be used for backing up data
What is the maximum speed that a dedicated fiber optic line can offer?
43 Tbps
What is the maximum speed Wi-Fi based on IEEE 802.11 standards can offer for 802.11n?
600 Mbps
What is the speed range for 3G cellular connections?
200 Kbps to 4 Mbps
What is the primary function of a network switch?
Transmit data only to the intended device
What is the maximum speed that cable line connections can reach?
160 Mbps
What is the primary function of a network router?
Manage traffic between networks
What is the primary function of a network bridge?
Manage traffic between segments of a network
What is the maximum speed that a satellite connection can offer?
15 Mbps
What is the maximum speed for Gigabit Ethernet?
1 Gbps
What is the maximum speed for Fast Ethernet?
100 Mbps
What is the primary difference between a server operating system and a desktop operating system?
Server operating systems can take on a particular role more effectively than a desktop OS.
What is the structure of a computer name on the Internet typically expressed as?
host.domain.tld
What is the naming structure called for a computer name expressed as host.domain.tld?
FQDN (Fully Qualified Domain Name)
What type of database is the DNS (Domain Name System)?
Distributed hierarchical database
What is the DNS naming hierarchy described as?
An inverted tree with the root at the top
What is the purpose of the DNS lookup process?
To resolve a computer name to an IP address
What is the term for the entire DNS tree?
DNS namespace
Which type of server contains the master copy of all DNS records for a domain?
Authoritative Server
What is the responsibility of Root Servers in the DNS hierarchy?
Managing top-level domain names
What is the primary function of DHCP (Dynamic Host Configuration Protocol) in networking?
Assigning IP addresses automatically
Which type of DNS query involves the local DNS server iteratively querying root and TLD servers to resolve the domain name?
Iterative query
What is the purpose of Forward Lookup Zone (FLZ) in DNS?
Resolving domain names to IP addresses
Which type of DNS zone is responsible for mapping IP addresses to domain names?
Reverse Lookup Zone (RLZ)
What role does the DNS client play in the DNS lookup process?
Resolving domain names to IP addresses
What is the purpose of a link-local address in IPv6 autoconfiguration?
To provide a unique address for communication within the local network
What does the Autonomous flag in a router advertisement message indicate in IPv6 autoconfiguration?
The prefix in the router advertisement can be used for address configuration
What is the primary function of a Web Server in a network environment?
Store, process, and deliver website pages to users using the HTTP protocol
What is the main function of an Email Server in a network environment?
Accept email and route it over the Internet using the SMTP protocol
What is the primary function of an NTP (Network Time Protocol) Server?
Serve 'correct' time and date requests
What is the primary function of an Authentication Server in a network environment?
Authenticate the credentials of users, usually account names and passwords
What is the primary function of a Proxy Server in a network environment?
Act as a mediator between a client program and an external server to filter requests
What is the primary function of an NIS (Network Information Service) Server?
Coordinate common configuration files across multiple computers in a LAN
What is the primary function of a Print Server in a network environment?
Manage printers and print requests within a LAN
What is the purpose of DHCPDISCOVER in the DHCP address assignment process?
To request an IP address from an available DHCP server
In IPv6, how can the network ID (prefix) be assigned?
Through stateless or stateful autoconfiguration or DHCPv6
What is the purpose of DHCPACK in the DHCP address assignment process?
To acknowledge the DHCP server's response, completing the transaction
What is a method for assigning the IPv6 interface ID?
Using the MAC address
When does the lease renewal process involve a DHCPREQUEST?
When the lease is 50% expired
In IPv6, what does the network ID (prefix) consist of?
Network ID and an interface ID
What is a common situation for lease renewal failure in DHCP?
Server inability to honor renewal and lack of server response
What is the purpose of the /etc/shadow file in a Linux system?
It contains the encrypted password and expiration information for each user.
What is the primary function of the pwconv command in Linux?
To revert from using two files (/etc/passwd and /etc/shadow) to one
What is the purpose of the authentication process in a Linux system?
To verify the user's identity using a valid username and password
What is the purpose of the /etc/passwd file in a Linux system?
It contains the user account information for each user.
What is the purpose of the pwck command in a Linux system?
To check the integrity of the /etc/passwd and /etc/shadow files
What is the purpose of the GUI in administering users and groups in a Linux system?
To provide a user-friendly interface for managing user accounts and groups
Which command is used to decompress files in Linux?
gzip -d
Which command is used for full and incremental backups in Linux?
dump
Which remote administration method for Linux servers does not encrypt communications?
Telnet
Which printing system is an older printing system with a lower compression ratio than gzip?
LPD
Which command is used to create, extract, and compress archives in Linux?
tar
Which compression utility in Linux supports long filenames and device files for backup and restore?
cpio
Which file contains encrypted passwords, last password change date, password expiration details, and account disablement information in Linux?
shadow file
Which command is used to modify user account information in Linux?
usermod command
What does the groupadd command do in Linux?
Adds a new group
Which command is used to compress all files in a directory in Linux?
gzip command
What is the purpose of the userdel -r command in Linux?
Removes the home directory and its contents
Which command is used to add members to a group in Linux?
usermod -G command
Which command in Linux is used to set the default printer for all users?
lpoptions -d
Which daemon in Linux logs all events and sends them to a database?
journald
Which network construct is used by logging daemons for communication between processes?
Socket
What is the recommended tool for restricting network service access in Linux?
TCP Wrapper
Which command in Linux is used to save firewall rules to a file?
iptables save
What directory typically stores log files for troubleshooting in Linux?
/var/log
Which command is used to manage zones and firewall rules for traffic by service or port number in Linux?
firewall-cmd command
What is the primary purpose of SELinux in Linux system security?
To enforce role-based security using security profiles and policies
Which encryption method is commonly used in Linux for protocols like SSH and GPG?
Asymmetric encryption
What is the potential security risk associated with SUID (Set owner User ID up on execution) in Linux?
It allows a file to be executed as the root user, potentially leading to system compromise
Which utilities in Linux are commonly used for monitoring system performance?
sysstat package, mpstat command, iostat command
Which tool can be used to detect intrusions in a Linux system?
Tripwire
Study Notes
Monitoring System Performance in Windows and Linux
- Windows Task Manager provides a Performance tab that gives a quick view of CPU, memory, disk, and network usage.
- The App History tab in Windows Task Manager shows usage history for Windows Store applications only, but this can be changed to show history for all processes.
- The Startup tab in Windows Task Manager shows which programs start automatically during system log-in and allows users to disable certain programs from starting up.
- The Users tab in Windows Task Manager shows the resources used by the user's account, other users on the system, and allows switching to other user sessions.
- The Services tab in Windows Task Manager allows users to view and manage system programs running in the background.
- Most Linux environments provide a system monitor, like the GNOME System Monitor, which monitors system processes, manipulates running applications, and displays resource usage history.
- The Processes tab in the GNOME System Monitor lists all processes running on the system and provides options to control displayed processes and view dependencies.
- The Resources tab in the GNOME System Monitor displays usage history of CPU, memory, swap memory, and network, and the File Systems tab includes information about disk space usage and file system type.
- The ps command in Linux lists system processes, their owners, and the amount of system resources being used, and assigns a Process ID (PID) to each process.
- The kill command in Linux is used to stop a process, with options like kill PID, kill -9 PID, and kill -SIGHUP PID, each serving different purposes.
- Performance monitoring tools are used to collect real-time data about a system's usage activities, establish performance baselines, and investigate potential system problems and bottlenecks.
- In Windows 10, Performance Monitor can be used to collect and view real-time data about a system's usage activities, including monitoring disk performance, managing memory, and monitoring processor use.
Network Communication and OSI Protocol Layers
- Network connections can be wireless (Wi-Fi, satellite, cellular) or cabled (Ethernet, phone lines, coaxial cables).
- Wi-Fi and Ethernet are common connections for homes and offices.
- A network adapter includes any network connector or wireless access circuitry and has a unique 48-bit MAC address.
- MAC addresses are used to locate a computer on a local area network (LAN).
- IP addresses are assigned to network devices when a connection is made, and MAC addresses are used in assigning IP addresses.
- IP addresses are used to find computers on the Internet and local networks using TCP/IP protocol.
- Port numbers uniquely identify the type of application on a computer and are added to the end of an IP address.
- The OSI Reference Model categorizes communication into seven layers, including the Physical Layer responsible for sending bits via transmission.
- The Data Link Layer interfaces with the physical hardware on the local network and uses MAC addresses for transmitting data.
- The Network Layer moves messages from one node to another using IP protocol and routing protocols such as ICMP and ARP.
- The Transport Layer is responsible for transporting application layer payloads using TCP for guaranteed delivery and UDP for fast transmission.
- The Application Layer describes the interface between two applications, includes protocols like HTTP, SMTP, POP3, and is often intertwined with the Presentation and Session layers.
Types of Network Connections and Hardware
- Networks are built using various technologies with different bandwidth capacities, measured in Kbps, Mbps, Gbps, Tbps, Pbps, Ebps, Zbps, and Ybps.
- Data throughput represents the average speed, while latency accounts for delays in network transmissions.
- Cellular connections include 3G (200 Kbps to 4 Mbps) and 4G (100 Mbps to 1 Gbps) technologies.
- Satellite connections, used in remote locations, offer speeds of up to 15 Mbps.
- Telephone line connections, such as ADSL, provide speeds of 640 Kbps upstream and up to 24 Mbps downstream.
- Cable line connections can reach speeds of up to 160 Mbps, depending on the cable type.
- Dedicated fiber optic lines offer speeds of up to 43 Tbps.
- Ethernet is a common LAN connection using twisted pair cabling, with Fast Ethernet at 100 Mbps and Gigabit Ethernet at 1 Gbps.
- Wi-Fi, based on IEEE 802.11 standards, offers speeds of up to 600 Mbps for 802.11n and uses frequencies at 2.4 GHz and 5 GHz.
- Networking hardware includes hubs that transmit data to all attached devices, switches that transmit data only to the intended device, bridges that manage traffic between segments of a network, routers that manage traffic between networks, and access points that allow wireless devices to connect to a wired network.
- Network topologies include star, bus, and hybrid (star-bus), with most networks using a star-bus topology.
- Each topology has its own unique arrangement of network elements and devices.
DHCP Address Assignment Process
- DHCP is a client/server protocol for IP address assignment.
- The process involves a four-packet sequence: DHCPDISCOVER, DHCPOFFER, DHCPREQUEST, and DHCPACK.
- DHCPDISCOVER is a broadcast packet requesting an IP address from an available DHCP server.
- DHCPOFFER is a response from the DHCP server offering an IP address and subnet mask.
- DHCPREQUEST is the client's response to accept the offered address.
- DHCPACK is the acknowledgment from the DHCP server, completing the transaction.
- The lease renewal process involves a DHCPREQUEST when the lease is 50% expired and a DHCPACK from the server.
- Common situations for lease renewal failure include server inability to honor renewal and lack of server response.
- IPv6 provides automatic address assignment without DHCP, but DHCPv6 can still be used for address assignment and management.
- IPv6 addresses consist of a network ID (prefix) and an interface ID.
- IPv6 network ID can be assigned through stateless or stateful autoconfiguration or DHCPv6.
- IPv6 interface ID can be assigned using the MAC address, randomly generated permanent or temporary identifiers, DHCPv6, or manual entry.
Linux System Security and Performance
- Firewall Daemon (firewalld) provides flexibility in configuring iptables through network zones and service names
- Network Zone defines trust levels for network connections and can be mutable or immutable
- firewall-cmd command manages zones and firewall rules for traffic by service or port number
- SELinux enforces role-based security using security profiles and policies to prevent insecure application access
- AppArmor provides similar protection to SELinux and can be enforced or used for warnings and log events
- Encryption algorithms use a key to scramble data and asymmetric encryption is commonly used in Linux, such as SSH and GPG
- Intrusions can be detected by analyzing log files, using PAM, lsof command, and detecting buffer overrun exploits
- SUID (Set owner User ID up on execution) allows a file to be executed as the root user, potentially leading to system compromise
- Intrusion Detection Systems (IDS) like Tripwire, AIDE, ICU, PortSentry, Snort, LIDS, and SWATCH can be used to detect intruders
- Performance monitoring utilities like sysstat package, mpstat command, and iostat command help monitor system performance
- The sysstat package contains utilities to monitor the system using information from the /proc directory and system devices
- mpstat command monitors CPU performance, even for multiple processors, while iostat command measures the flow of information to and from disk devices
Test your knowledge of system performance monitoring in Windows and Linux with this quiz. Explore tools like Windows Task Manager and Linux system monitor, and learn about commands like ps and kill in Linux.
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