A+ cert notes ​
I am currently studying to get my CompTIA A+. I want you to act as if you are my tutor preparing
me for the test.
1 am going to ask you about a bunch of different concepts, I want your answers to include a few
things. General overview of concept
2. What I might need to know about it for the A+ exam: Answer all of my questions in this
format, until I say otherwise, Can you do that for me?
PRL- preferred roaming list. Uses service provider ids allowing the device to establish
connections with the right cellphone tower
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Acquisition table- lists the frequencies the device should search for networks
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System table- prioritizes the network the device should connect to and which to avoid
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POP3(Post office protocol) - is a standard protocol used by email clients to retrieve
email from a mail server. It allows email; clients to download messages from the server to the
local computer, where they can be read and managed. POP3 uses the ports 110 and 995. With
port 110 being the default port for POP3 communication. And port 995 being used over
SSL\TLS, which provides a secure and encrypted connection. Can’t be used to send emails,
only receive them from a mail server.
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SNMP(Simple network management protocol) - is a protocol for managing and
monitoring network devices. It uses agents and managers to collect and analyze data, providing
insights into network performance and device status. Operating on port 161 and 162, with 161
the default port used for SNMP requests and responses, and port 162 used for SNMP trap
messages, which are notifications sent by the agents to alert the manager of certain events or
conditions. While there is not port for being secure in version 1 or 2 version 3 of Simple network
management protocol are secure by default
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SMTP(simple mail transfer protocol) - is a standard protocol used to handle sending and
receiving email messages over the network. It facilitates the transfer of email from client to
server and between servers until it reaches the recipient's mailbox. Using port 25 by default it is
commonly used to send mail. With port 587 often used for submitting emails from client to an
email server with STARTTLS encryption. And finally using port 465 sometimes used smtp over
ssl\tls though it is not officially recognized by the IETF. SMTP is a very simple protocol and
doesn't support mail retrieval from the servers.
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POP3 - is used for retrieving emails from a mail server and makes them available locally
then deletes the mail from the server. Only really used to review emails.
Uses ports 110 by default and uses port 995 for secure connections
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Imap or (internet message access protocol) - synchronize emails from server to client.
Much more advanced than pop3. IMAP also has advanced management controls, such as
folder,partial downloads, and multiple devices. Uses ports 143 for non encrypted and 993 for
encrypted ssl/tls connections.
FTP(File transfer protocol) - as the name states this facilitates file transfers. Using ports
20 and 21, with port 20 as the default port used for FTP data connection in active mode and port
21 as the control connection. FTP does not have encryption like FTPS and SFTP. while FTP can
get files around it does not have the security of FTPS and SFTP
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Telnet - is a network protocol that allows remote communication between a client and a
server. By using a command line interface you can manage internet connected devices. On
port 23 of communication. Telnet is an unencrypted form of communication.
SSH(Secure shell) - Is the better version of Telnet as it is an encrypted protocol.
Operating on port 22 it is still a command line interface, but can also provide secure file transfer
and tunneling network traffic. ​
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WISP (wireless internet service provider) - a internet service provider that delivers
internet to customers using wireless connections. Mostly used for rural areas. From the provider
to the customer the provider mostly if not all of the data is transferred wirelessly. ​
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NSP (network service provider) - provides network infrastructure survivors to other
service providers, large corporations and sometimes end-users. Mostly used for high capacity
networks. NSP can be used by ISPs to get regular consumer internet for a large area through
wholesale arguments.
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ISPs are responsible for delivering Internet access to end-users, managing the last-mile
connections, and offering various consumer-oriented services.
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TSP (telephone service provider)- is a company that provides a wide range of
telecommunications services to customers. Can also provide services to end users and
corporations like Verizon and AT&T. like broadband for fiber optic voIP and mobile networks like
LTE of 5G. Mostly act as infrastructure managements and data centers and the cables that
provide the data.
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ACL (access control list) - is a rule based access control mechanism implemented on
routers, switches, and firewalls. When used on routers ACLs can filter incoming and outgoing
traffic based on specified rules, controlling which packets are allowed or denied. On switches
ACLs are used to restrict traffic between VLANs. For firewalls ACLs define security policies.
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WLAN (wireless local area network) - is a local area network that utilizes wireless
communication. Mostly used in
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MAN (metropolitan area network) - used to connect government buildings is a city
interconnected so they can share information quickly and effectively. Can also be utilized by
universities campuses. to
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WWAN(wireless wide area network) - refers to wireless networking that provides internet
access over a large geographical area. WWANs typically decdibe cellular networks
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VLAN (virtual local area network) - a network configuration that segments a physical lan
into multiple logical networks. Used in mid to large businesses to digitally separate different
parts of a company so if one gets hacked the others can still perform their job function.
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MAN(metropolitan area network) - is a type of network that covers a larger geographical
area than a local area network but smaller thanks to a wide area network. Mans are designed to
provide high speed data connections across a city or a large campus, enabling communication
and multiple lans and other networks within the metropolitan area.
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MMC (microsoft management console) - customizable framework providing access to a
collection of system tools designed to manage networks, computers, services. Users can
change what information is displayed when the program is opened. So technicians can at a
glance see what might be wrong or is being overused.
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ATM (asynchronous transfer mode) - a network protocol for connecting devices on a
wan. Uses cell based switching to move fixed sized amounts of data for an efficient and
predictable data transfer. ATM can be used for both local area and wide area networks.
Supporting high speed transfer over long distances.
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Wi - Fi (Wireless Fidelity) - refers to the wireless networking used to connect devices
within a local area network. WiFi Standards are made by the IEEE which define the protocols for
wireless networking
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802.11a: Operates in the 5 GHz band with a maximum data rate of 54 Mbps.
802.11b: Operates in the 2.4 GHz band with a maximum data rate of 11 Mbps.
802.11g: Operates in the 2.4 GHz band with a maximum data rate of 54 Mbps.
802.11n: Operates in both the 2.4 GHz and 5 GHz bands with a maximum data
rate of 600 Mbps.
○​ 802.11ac: Operates in the 5 GHz band with a maximum data rate of 6.933 Gbps
supports MIMO and beyond.
○​ 802.11ax (WiFi 6): Operates in both the 2.4 GHz and 5 GHz bands (and
beyond), offering higher efficiency, increased capacity, and improved
performance in dense environments. With speeds reaching 9.6 Gbps
○​ 802.11be (WiFi 7) operates in the 2.4 GHz, 5 GHz, and 6 GHz bands, similar to
WiFi 6E but with enhanced capabilities. With speeds reaching 46 Gbps.
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ARP (Address Resolution Protocol) - used for mapping ip Addresses to mac addresses
within a local network segment, and is not used for wan connections. Allows connections from
mac addresses (layer 2) to translate to IP addresses at layer 3. The arp -a command can be
used to see the arp table and the arp -d* to clear everything. This can be used after a change to
the network topology.
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Daas (Desktop as a service)- used to enable remote access through a thin client. Can be
used to allow for cheaper hardware cost and is more flexible on how many people can be
working you can easily add or remove people through the service.
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NaaS(network as a service) - is a cloud service model that provides network services on
a subscription basis. NaaS allows businesses to acquire networking capacity without owning or
managing physical hardware. It involves renting network infrastructure, such as routers,
switches, firewalls and bandwidth, from a third party provider. This model is scalable and
flexible, enabling organization to adjust to their networking needs
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SDN (software defined networking) - an approach to networking that uses
software-based controllers or applications programing interface or api. Is used to separate the
control plane from the data plane using software based resource management. Mostly used in
data centers and larger companies as it is scalable and offers enchanted security.
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LDAP (lightweight directory access protocol) - is used to access manage and directory
services over the network. While it is similar to Microsoft's active directory it’s different, and often
used in conjunction with ADs. similar to AD it controls directory structure, standard operations,
and can be used as an authentication and authorization software.
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OID(object identifier) - is a system used to name objects in a hierarchical structure. OIDs
are very similar to LDAP directories, SNMP MIBs, and other digital certificates, providing a
standardized way to identify and manage objects across different systems and platforms.
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GUID(globally unique identifier) - is a unique string of characters used to identify
hardware, and data it is widely used in software applications to ensure that every identifier is
unique across different systems and platforms. is similar to OIDs but is mostly used for
hazardware and data not in a hierarchical way.
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WAP(wireless access protocol) - is designed to enable wireless devices, such as mobile
phones, to access and interact with internet services and applications. This is largely a legacy
protocol and has been replaced with 4g\LTE-A and 5G mobile networks.
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RIS(Radio Interface Specification) - a specification related to the radio interface in
telecommunication. It outlines the standards and protocols for the communication between
mobile devices and the network interface. Guides mobile devices on which radio frequencies
are available to ensure efficient communication within various networks. And is crucial to
development and operation of cellular networks.
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PRI(primary rate interface) - is a telecommunication standard used to carry multiple
voices and data transmission over a single physical line. It is commonly used for business for
large scale settings communication and data services, offering high capacity and reliability.
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MDM(mobile device management) - a solution to manage, secure, and monitor mobile
devices within an organization. With features like device configuration, security policy
enforcement, application management, and monitoring, ensuring that mobile devices adhere to
organizational standards and requirements.
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MFD(Multi functional devices) - also known as multi function printers(MFP) combining
printing, scanning, copying,and faxing into one unit. This can save space and cost for the
company if all functions are needed but are more using up the space of one machine. It is
commonly used in office environments.
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MAM(mobile app management) - is used to manage the mobile apps on devices in the
name of ensuring company policy and security and compliance. Often will be used in
conjunction with MDM to provide comprehensive management of mobile devices. This controller
allows IT teams to remotely update, install or remove applications for an employee's device.
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UEM(Unified endpoint management) - provides a comprehensive approach to managing
and securing a wide range of endpoints, including desktops, laptops, mobile devices, and IoT
devices from a single platform. It offers centralized management, and robust security features
making it ideal for large organizations with diverse device environments.
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RDP(Remote Desktop Protocol) - is a microsoft developed protocol that provides
graphical access to computers, enabling users to interact with remote desktops as if they were
physically present. Operation on port 3389, RDP is commonly used for remote administration
and remote work, offering a user friendly interface. While RDP includes encryption and sessions
management features it is advised to implement additional security measures, such as firewall
and VPNs, to ensure secure connections.
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NeTBIOS(network basic Input\Output System) - is an api that allows applications on
different computers to communicate over local area networks \ LAN. communicates over port
137, 138, 139. The system as a whole is mostly used for file sharing and printer sharing over
windows. Even with NeTBIOS’s know security vulnerabilities it is still a integral part of many
Local Area Networks.
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NetBT(NeTBIOS over TCP/IP) - is a protocol that allows NeTBIOS to run over TCP/IP
protocol suite. It provides the same function as NeTBIOS, such as name resolutions and
session services, but does so over a TCP/IP network, making it suitable for modern networks
that use the TCP/IP protocol.
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IMAP4(Internet Message access protocol version 4) - is a protocol used by email clients
to retrieve messages from a mail server. Unlike POP3, which primarily downloads emails to a
single device, IMAP4 allows for more sophisticated management of emails directly to the mail
server, enabling synchronization across multiple devices. This would allow multiple devices from
the user to all have the same information, as they are just accessing the file on the server acting
as a thin client. IMAP4 uses ports 143 as the default connection and 993 for encrypted ssl/tls
connections.
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SMB(Server message block) - is a protocol that is used for file sharing printers and other
resources on a network. It operates on port 445 and when using NetBIOS the protocol uses
TCP\UDP on ports 137-139. The protocol is supported on all major OSs like Linux and MacOS.
There are multiple versions on SMB with version 1 being insecure and out dated. Versions 2
and 3 are imported performance and secureit, version 2 was introduced with windows vista, and
3 being the newest and best version was introduced with windows 8 and server 2012 with better
scale ability.
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CIFS(common internet file system) - similar to SMB(Server Message Block). Used to
share files and printers over the network. It is an extension of SMB and is primarily used in
windows, but can be used in linux. it can support user authications making the user have to
provide credentials to access the files on servers that have the protocol.
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Samba - is an open source software that provides file and printer services to SMB/CIFS
clients. It allows Unix Like systems to interact with Windows systems using the SM/CIFS
protocol, enabling file and printer sharing between different operating systems. Samba is
configured to act like a domain controller, allowing it to manage authentication and authorization
for windows clients in the network including the account permissions.
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H.323 is a set of protocols by th eInternational Telecommunication Union for voice video
and data communication across IP networks including the internet, it is widely used for voice
over IP and videoconferencing. The standard is interoperable and should work on all major OS.
The H.323 includes standards like the H.225, H.245 RTP, and RTCP.
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TCP(Transmission control protocol) - this is the core of most things on the internet as it
handles the internet protocol. It is designed to provide reliable, ordered and error-correct
delivery of data between applications running on hosts communicating via an IP network. TCP
works by establishing connection before transmitting data and ensures that all packets are
received and in order. Then acknowledgments are sent to ensure the delivery of data. During
the transmission phase the data flow is controlled to check for network congestion and to make
sure that the receiver is not overwhelmed. Then it is error corrected to detect and correct false
data. This all happens and the data is also checked to see if the data was received in the
correct order. The 3 way handshake is a SYN, SYN-ACK. ACK. SYN:the client sends a SYN
packet to the server to initiate a connection. Then SYN-ACK is the server that responds with a
SYN-ACK packet. Finally the ACK is sent from the client to establish the connection.
HTTP: Port 80
HTTPS: Port 443
FTP: Ports 20 and 21
SMTP: Port 25
Telnet: Port 23
SSH: Port 22
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TCP vs. UDP - TCP is used to ensure that data is sent but can be much slower than
UDP which is focused on real time data transfer, and doesn't care if all the data is received or is
lost. This connection is used in gaming and streaming.
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UDP(User Datagram Protocol) - is a conncetionless protocol thaty allows for the fat
treasmition of data with minmal overhead. It does not garinete deivleory, order or error
correction, makingit sutible for real time communication where some lost is acceptable.
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DSL(digital subscriber line) - provides internet access through telephone wires straight to
the ISP. This can ensure that the bandwidth is consistent and not shared with the neighbors.
With DSL you need a DSL motel which converts the digital signal to an analog signal. Central
Office Proximity: The quality and speed of DSL service decrease with the distance from the
central office. The farther you are, the lower the potential speeds.
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Demarc(Demarcation point) - is a term used to describe the point at which the public
network of a telecommunication company ends and the private networks of the customer
begins. This point marks the boundary between the service provider's responsibility and the
customer's responsibility.
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ONT(optical Network terminal) - its main function is to convert fiber optic signals from the
isp to electrical signals.
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MDI(medium dependent interface) - is a term used to describe what is moving the data,
like ethernet cables. MDI includes NICs wireless and ethernet ports. Like straight through cables
and crossover cables.
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Straight through cables - when connecting devices with different interfaces like
a computer to a switch.
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Crossover cable - when connecting devices with similar interfaces like a switch
to a switch, or a computer to a computer.
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The need for the crossover cable and the straight through cable can be
overcome with MDI-X as most modern devices can communicate and agree that the cable is
wrong and compensate for that.
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IDF(Intermediate distribution frame) - is the secondary distribution point within a
building's networking. It connects to the main distribution frame and helps extend the reach of
the network. Unlike the MDF the IDF distributes to the individual user
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MDF(Main Distribution frame) - is a curtal component in telecommunication where the
telecommunication and networking within a building meet. It serves as the central hub for inter
network and external networking.
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MIMO(multiple input multiple output) - uses multiple transmitters and receivers to send
and receive more data faster. This has more effect than just data speeds but also range, with
areas with more observations and reflections the data has a better chance to get to at least one
receiver. You can also have it transmit on multiple signals in case the area is congested.
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Yagi Antenna - Directional: Yagi antennas focus the signal in a specific direction,
making them suitable for long-range point-to-point links.
High Gain: They provide higher gain compared to omnidirectional antennas, improving signal
strength and range.
Omnidirectional Antenna - An omnidirectional antenna is a type of antenna that
radiates or receives radio signals uniformly in all horizontal directions. Unlike directional
antennas that focus energy in specific directions, omnidirectional antennas have a
non-directional radiation pattern in the horizontal plane. They’re commonly used in
wireless devices like wireless routers, cell phones, FM radios, and walkie-talkies.
Unidirectional Antenna - Directional: Similar to Yagi antennas, unidirectional antennas
focus the signal in a specific direction, making them suitable for long-range links.
High Gain: Provides high gain, improving signal strength over long distances.
Parabolic Antenna - Highly Directional: Like dish antennas, parabolic antennas focus
the signal very narrowly, providing high gain and making them ideal for long-range point-to-point
links. High Gain: Offers very high gain, essential for maintaining a strong signal over long
distances.
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Syslog server - is a type of server that collects, stores and analyzes long data from
various networked devices. It provides a centralized place for logs for all sorts of devices such
as routers, switches, firewalls, and other servers.
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UTM(Unified threat management) - is an all in one security solution that has many
security functions into one device. It integrates firewall, antivirus, intrusion and
detection\prevention, spam filtering, VPN, web filtering, application control, and data loss
prevention. With application/prevention you can control how specific applications can be used in
order to prevent misuse with company policies.
SCADA(supervisory control and data acquisition) - it is a type of control system used in
industrial and manufacturing settings to monitor and control process and machinery. It allows
operators to gather real time data from various sensors and equipment, analyze this data and
control the process remotely.
EDR(endpoint decision and response) - is cybersecurity technology focused on
detecting, investigating and responding to suspicious activities and threats on endpoints such as
computers, servers and mobile devices. It provides real time monitoring and data collection and
automated responses. After the threat has been removed from the network the data can be
used to do forensic analysis.
ESN(Electronic serial number) - is a unique identifier assigned to mobile devices,
specifically for CDMA(Code Division Multiple Access). It is used by cellular technology networks
to identity and authenticate devices on the network. These technologies extended to
MEID(Mobile equipment identifier) and IMEI(International mobile equipment identifier) used
primarily for GSM(Global system for mobile communication)deives but is also used on newer
CDMA devices.
GSM(Global system for mobile equipment identifier) - is standard developed to describe
protocol for second generation 2G digital networks used by mobile phones. GSM became the
global standard for mobile communication, with over 90% market share. GSM operates on the
900MHz in europe and Asia, and 800MHz 1900MHz in america.
CDMA(code division multiple access) - is a digital technology used for mobile
communications unlike GSM, which uses time division multiple access TDMA, CDMA uses
spread-spectrum technology and unique codes to allow multiple users to be multiplexed over
the same physical channels.
Class A Private Address:
●​ Range: 10.0.0.0 to 10.255.255.255 (10.0.0.0\8)
●​ Subnet Mask: 255.0.0.0
Class B Private Address:
●​ Range: 172.16.0.0 to 172.31.255.255 (172.16.0.0\12)
●​ Subnet Mask: 255.240.0.0
Class C Private Address:
●​ Range: 192.168.0.0 to 192.168.255.255
●​ Subnet Mask: 255.255.0.0
APIPA(Automatic private address IP addressing) - is a feature in windows that allows a
computer to automatically assign itself an IP address from the APIPA range when a DHCP
server is not available. The address lock is from 169.254.00 - 169.254.255.255.
MX Record(Mail Exchange) - is DNS used to designate the mail servers for a domain,
directing email traffic. It includes a priority value to handle multiple mail servers, ensuring email
can be delivered even if the primary server is unavailable.
AAAA record(IP address record) - is for ipv6 IP addresses. AAAA record is crucial for
supporting IPv6 connectivity, storing the data at 128 bit, allowing devices to use the newer IPv6
protocol to reach a domain.
CNAME(Canonical name record) - CNAME record in DNS is used to map alias damon
name to another canonical damon name, providing a way to manage multiple domain names to
a single domain name.
PTR(pointer record) - in DNS is used to map IP addresses to a domain name, enabling
reverse DNS lookups. This is important for verifying server identities and often used in email
server configurations to match IP addresses with domain names.
TXT(TEXT Record) - are versatile and can store various types of text-based data,
including configuration information and domain verification details. They are particularly useful
for tasks such as setting up SPF records for email authentication and verification domain
ownership.
DMARC(domain-based message authentication reporting and conformance) - is an
email authentication protocol that helps protect domains from email spoofing by leveraging SPF
and DKIM.it allows domain owners to set policies for handling emails that fail authentication
checks and to receive reports on email activities to their domain.
DKIM(Domain keys identified mail) - is an email authentication method designed to
detect forged sender addresses in emails, a technique often used in phishing and email scams.
It allows the receivers to check that an email claimed to come from a specified domain was
indeed authorized by that domain. This is achieved through cryptography authentication.
SPF(Sender policy Framework) - is an email authentication designed to prevent email
spoofing. SPF allows the owner of a domain to specify which mail servers are permitted to send
emails on behalf of that domain. Helps prevent email spoofing and puts a list in TXT DNS that
contains all the mail servers that are allowed to send emails from that domain.
SRV(SRV records)- are a type of record used to define the location IE. the hostname
port number of a server for specified services. They are particularly useful for applications
and services that need to locate a server providing a specific service without hard
coding the server’s address. SRV records are often used in environments such as Active
Directory, VoIP and instant messaging services.
ADSL(Asymmetric digital subscriber line) - is the most common type of DSL internet
access. is used for transmitting digital data overtrading copper telephone lines. It is called
symmetric because it provides higher download speeds than upload, making it well suited for
interment users that don't upload.\
A DNS record stores data in 32 bit records. cna most commonly used to map IP address
to hostnames
AAAA DNS database is used for IPv6 addresses most commonly used to map
hostnames to IP addresses.
UTP(unshielded twisted pair) - is a type of copper cabling commonly used in networking
and telecommunication. UTP cables consist of insulated copper wire twisted together to reduce
electromagnetic interference and crosstalk. They don't have an additional shielding layer making
then lighter and more flexible and less expensive.
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STP(shielded twisted pair) - is the counterpart to UTP. It is a type of network cable that
has pairs of insulated copper wires but with additional shielding around each individual wires to
further protect against crosstalk and EMI electromagnetic interference. While more expensive it
can protect your data better.
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Network mapper - is a device not in person but on the computer program that is open
source to trace the networking to scan larger networks. Used to discover hosts, services,
operating systems and vulnerabilities. Network mapping is also called nmap.
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DBC(direct burial cable) - is a network cable specifically meant for installation
underground without the need for additional prevention. These cables are constructed to
withstand harsh environments such as acid, physical, moisture.
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USB 2.0
●​ Introduced: 2000.
●​ Data Transfer Rate: 480 Mbps (High Speed). Max 5 meters
●​ Connectors: Type-A, Type-B, Mini-USB, and Micro-USB connectors were commonly
used.
●​ Backward Compatibility: USB 2.0 is backward compatible with USB 1.1.
●​ Power Delivery: Up to 500 mA (milliamps) of power, enough to power small devices.
●​ Use Case: Widely used for a variety of peripherals, such as flash drives, external hard
drives, and more.
USB 3.0/3.1/3.2
MAX Length: about 3 meters
●​ Introduced:
○​ USB 3.0: 2008 (also known as USB 3.1 Gen 1).
○​ USB 3.1: 2013 (also known as USB 3.1 Gen 2).
○​ USB 3.2: 2017.
●​ Data Transfer Rates:
○​ USB 3.0: 5 Gbps (SuperSpeed).
○​ USB 3.1 Gen 2: 10 Gbps (SuperSpeed+).
○​ USB 3.2 Gen 1: 5 Gbps (Superspeed USB)
○​ USB 3.2: Up to 20 Gbps (using multi-lane technology).
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USB4
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Introduced: 2019.
Data Transfer Rate: Up to 40 Gbps (similar to Thunderbolt 3).
Connectors: Primarily uses USB Type-C connectors.
Backward Compatibility: Compatible with USB 3.x and Thunderbolt 3 devices.
Features:
○​ Integrates Thunderbolt 3 technology.
○​ Supports DisplayPort and PCIe over USB.
○​ Improved power delivery, supporting up to 100W.
●​ Use Case: High-performance peripherals, external GPUs, high-speed data transfer.
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RS-232 - can be used for connecting mice, modems, and other peripheral devices.
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Thunderbolt standards
Thunderbolt 1 introduced in 2011
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Max speed of 20 Gbps with both channels
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Uses a Mini displayport (MDP)
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Supports video
power delivery up to 10 watts
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Compatible with Mini Display port
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Able to daisy chain up to 6 devices
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Up to 3 meters over copper
Thunderbolt 2
Thunderbolt 2 was introduced in 2013
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Max speed of 20Gbps with both channels
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Mini DisplayPort connector
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Supports displayport 1.2
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Power delivery up to 10 watts
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Daisy chaining up to 6 devices
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Up to 3 meters over copper
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Thunderbolt 3
Thunderbolt 3 was introduced in 2015
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Max speed of up 40 Gbps
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Type - C connector
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Supports displayport 1.2 and 1.4 up to 8K display
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Power delivery up to 100 watts
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Daisy chain up to 6 devices
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Compatible with USB 3.1 or later
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Can have PCIe 3.0 by 4 lanes
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Backwards compatible with adapter.
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Up to 0.8 meters without drop in speeds on copper
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Up to 60 meters on fiber
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Thunderbolt 4
Thunderbolt 4 was introduced in 2020
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Max speed of 40 Gbps
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Type - C connector
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Displayport 1.3 allowing up to a 8k display
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Daisy chain up to 6 devices
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PICe 3.0 by4 lanes
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Introduced intel VT-d based DMA (direct access memory) to protect against DMAattacks
Backwards compatible with all thunderbolt with adapter
Up to 0.8 meters without drop in speeds on copper
Up to 60 meters on fiber
SCSI(small computer system interface) - is a set of standards for connecting and
transferring data between computers and peripheral devices. It was widely used in the past for
connecting hard drives primarily but can be used for scanners, printers and other peripheral
devices.
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DVI- standards
DVI-A
Analog only
12 + 5 pins 17 total
Mainly used for CRTSand is similar to VGA
Can be used for passively with VGA
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DVI-D (Digital)
Digital only
Single link DVI-D 18+1 pins
Dual link DVI-D 24+1 pins
Mostly used for digital displays like LCD’s
Can’t be a passive transition from VGA to DVI-D
Single link DVI-D supports up to 1920x1200 at 60Hz
Dual link can support up to 2560x1600 at 60 Hz
DVI-I (Intagerated)
Carries both digital and anolog.
Single link 18+5 pins
Dual link 24+5 pins
Versatile connectotion type that can be used with digital and analog displays
Can be used with GA without a active adapter
Same resolutions as DVI-D
OCR scanner (optical character recognition)​ - are devices or software applications that
convert different types of paper documents that have been scanned by an digital scanner and
convert them to machine readable text.
IRC scanner(intelligent character recognition) - are scanners that are specialized
systems or software designed to recognize and interpret hand written text. Unlike OCR which
focuses on printer text, ICR is tailored to reading and digitizing handwritten inputs like forms and
surveys.
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magnetometer - is a device used to measure the direction and strength of a magnetic
field. Often used to find hidden metal objects and are used to screen people before entering a
secured area.
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Least privilege - is used to keep information that is above someone's pay grade for being
accessed by that person. The rule states that someone is only granted the minimum level
access necessary to perform their job function. Used to reduce risk of sensitive information
leaks and misuse.
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CRL(Certificate revocation list) - a list by a certificate Authentication (CA) that contains
information about digital certificates that have been revoked before their scheduled expiration
data. The CRL helps ensure that certificates are no longer valid due to compromise, expiration
or other reasons are not trusted or used in security operations
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NAT(Network address translation) - used to conservet the number of public ip addresses
by re-routing the packets on the local network so that the local network is a private address and
the router is public. Is a network technique used to modify the source or destination IP
addresses in packet header as they pass through a network device, typically a router or firewall.
NAT is primarily used to enable multiple devices on a local network to share a single public IP
address for accessing the internet, thus conserving the number of public addresses required
and enhancing security.
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BCP(business continuity planning) - is the process of creating strategies and plans to
ensure that a business can continue operating in the event of a disruption or disaster. BCP
involves identifying potential threats, assessing their impact on business operations and
minimizing downtime and ensuring recovery.
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CSR(Certificate signing request) - is a block of encoded text generated on a server that
contains information about the entity requesting a digital certificate. It is sent to a certificate
authority to apply for a digital certificate which can then be used for secure communication and
authentication ​
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DLP(Data loss prevention) - a set of technologies, policies, and procedures designed to
prevent unauthorized access, leakage, or loss of sensitive data. DLP solutions monitor, detect,
and respond to potential data breaches or leaks to protect sensitive information from being
leaked.
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AUP(Acceptable use policy) - set of rules that define occupational and unacceptable
behavior regarding the use of an organization's network systems, and resources. An AUP is
designed to ensure that users adhere to security and usage standards to company assets and
operational infertility.
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POTS(plain old telephone service) - refers to the traditional analog telephone system
that has been in use since the late 19th century. It operates over copper telephone lines and
provides basic voice communication. POTS lines use circuit-switched technology, where a
dedicated line is established between two points for the duration of the call.
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PaaS(platform as a service) - a cloud computing model that provides a platform and
environment for developers to build, deploy, and manage applications without having to worry
about the underlying infrastructure that includes development tools, databases, middleware,
operating system , and cloud infrastructure, all managed by the cloud service provider.
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VDI(virtual desktop infrastructure) - is technology that hosts the desktop environments
on a centralized server and delivers them to end users over the network in a CDI setup, users
access virtual desktops that run on virtual machines hosted by a data center. This allows users
to have a consistent and secure desktop experience from any device or location as long as they
have a network connection.
Steps to troubleshoot
Step 1: Identify the problem. ...
Step 2: Establish a theory of probable cause. ...
Step 3: Test the theory to find out the cause. ...
Step 4: Create an action plan. ...
Step 5: Implement the solution or escalate as necessary. ...
Step 6: Verify full system functionality and implement preventive\Educate
the user
macOS terms
Finder - File system
Spotlight - system search utility
Keychain - password manager
iCloud - apple's cloud storage
Remote Disk - network attached storage. Might also allow for disks on other computers to be
accessed.
Dock - the taskbar
Disk Utility - disk maintenance tool
File vault - like bitlocker full disk encryption
Terminal - command prompt like
Force Quit - is used to terminate apps.
Linux command
Ls - is to show files and working directories
Pwd - print working directory
Grep - used to search plain text file for patterns or regular expressions
Ps - process status like task manager
Dir - list the contents of the working or specified directory
Rm - remove here
Mv - Move files and directories from one location to another within a file system.
Chmod - change the permissions of files and directories. Permissions determine who can read,
write, or execute a file.
Chown - change the ownership of files and directories
Usermod - or modify user command is used to change the properties of a user
Su - used to switch users using the command line interface. Su stands for substitute user or
switch user.
Sudo - or super user do is a command that is like run as administrator.
apt-get - is the most popular package manager on Debian-based linux can be used to install
update
Yum - Yellowdog updater, modifier. It is a powerful package manager tool that simplifies the
process of installing and managing software. On red hat distros like centOS and fedora.
Synaptic - you can launch a synaptic package manager by running this.
ip - is present in net-tools which are used to show or manipulate routing, devices, and tunnels.
Ifconfig - is a deprecated command in net-tools similar to ip.
df - is used to see the ‘disk free’ space is on the system
cp - is used to copy individual files or multiple files or entire directories.
nstat - or netstat provides network statistics.
To get help on a command you can type man [program name]
top - is a command that shows task manager like features
Isostat - command is used for monitoring system input/otuput device loading. Lets you monitor
cpu I/O statistics of all disks and file systems.
traceroute - is a command used to print the hops a packet used to get to your host system.
Cat - allows users to view concrete create copy merge and manipulate file contents.
dd - a low lever utility that can create copies of disk partitions
cpio - can create and extract archived files and is used with other commands to create backups
rsync - can be used for copying and syncing files and directories locally and remotely
tar - widely used for archiving multiple files into a single file used to compress file size for
backup
dump - a utility designed for backing up file systems and can restore the backup later.
dig - is used to administer connadn-line DNS queries
find - used to search or find files and directories
nano - is used to as a command line text editor
gedit - is the default graphical software used to edit text on linux
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