CompTIA Network+ Concepts I Struggled With

These are some key ideas I struggled with, so here I can practice them.

Class A Private Address Range

10.0.0.0 - 10.255.255.255

Class B Private Address Range

172.16.0.0 - 172.31.255.255

Class C Private Address Range

192.168.0.0 - 192.168.255.255

Loopback Address

127.0.0.1

APIPA Address Range

169.254.1.1 - 169.254.254.254.

Multicast Address Range (Class D)

224 – 239.255.255.255

Experimental Address Range (Class E)

240 - 255

T568A

1. Green/White

2. Green

3. Orange/White

4. Blue

5. Blue/White

6. Orange

7. Brown/White

8. Brown

T568B

1. Orange/White

2. Orange

3. Green/White

4. Blue

5. Blue/White

6. Green

7. Brown/White

8. Brown

802.11a

·         Operates in the 5 GHz range

·         54 Mbit/s

·         Not common today

802.11b

·         Operates in the 2.4 GHz range

·         11 Mbit/s

·         Not common today

802.11g

·         Operates in the 2.4 Ghz range

·         54 Mbit/s

·         Backwards-compatible with 802.11b

802.11n

·         Operates at 5 GHz and/or 2.4 GHz

·        150 - 600 Mbit/s

·         4 x MIMO

Also known as (Wi-Fi 4)

802.11ac

·         Operates in the 5 GHz band

·         867 Mbit/s - 6.9 Gbit/s

·         8x DL MU-MIMO

Also known as (Wi-Fi 5)

802.11ax

·         Operates at 5 GHz and/or 2.4 GHz

·         1,201 Mbit/s - 9.6 Gbit/s

·         8x DL and UL MU-MIMO

·         Orthogonal frequency-division multiple access (OFDMA)

Also known as (Wi-Fi 6)

802.1X

·         IEEE Port-based Network Access Control, you don’t get access until you authenticate

·         Talking about physical interfaces, not TCP/UDP ports

·         Makes extensive use of EAP and RADIUS (Extensible Authentication Protocol and Remote Authentication Dial In User Service)

·         Admin enable/disable ports

·         Duplicate MAC address checking

Also known as “Network Access Control” (NAC)

Category 3 Cable

Cable Type: UTP

Network Application: 10BASE-T

Max Distance: 100m

Frequency: 16 MHz

Connector: RJ-45

Category 5 Cable

Cable Type: UTP

Network Application: 100BASE-TX

Max Distance: 100m

Frequency: 100 MHz

Connector: RJ-45

Category 5e Cable

Cable Type: UTP or F/UTP

Network Application: 1000BASE-T

Max Distance: 100m

Frequency: 100 MHz

Connector: RJ-45

Category 6 Cable

Cable Type: UTP, F/UTP, or U/FTP

Network Application: 1000BASE-T or 10GBASE-T

Max Distance: 100m for 1000BASE-T and 55m for 10GBASE-T

Frequency: 250 MHz

Connector: RJ-45

Category 6a Cable

Cable Type: UTP, F/UTP, U/FTP, or S/FTP

Network Application: 10GBASE-T

Max Distance: 100m

Frequency: 500 MHz

Connector: RJ-45

Category 7 Cable

Cable Type: S/FTP or F/FTP

Network Application: 10GBASE-T

Max Distance: 100m

Frequency: 600 MHz

Connector: GG45/TERA

Category 8 Cable

Cable Type: 40GBASE-T

Network Application: U/FTP, F/UTP, F/FTP, or S/FTP

Max Distance: 30m

Frequency: 2000 MHz

Connector: RJ45 or GG45/TERA

100BASE-FX

Optics: 1300nm

Cable: MMF (OM1/2)

Max Distance: 2km

Connectors: ST, SC, MT-RJ

100BASE-SX

Optics: 850nm

Cable: MMF (OM1/2)

Max Distance: 550m

Connectors: ST, SC, LC

1000BASE-SX

Optics: 850nm

Cable: MMF (OM1/2/3)

Max Distance: OM1:275m and OM2/3: 550m

Connectors: ST, SC, LC, MT-RJ

1000BASE-LX

Optics: 1300nm 1310nm

Cable: MMF (OM1/2/3) and SMF (OS1/2)

Max Distance: OM1: 33m, OM1/2/3: 550m, and OS1/2: 5km

Connectors: SC, LC

10GBASE-SR

Optics: 850nm

Cable: MMF (OM2/3)

Max Distance: OM2: 82m and OM3: 300m

Connectors: SC, LC

10GBASE-LR

Optics: 1310nm

Cable: MMF (OM4) and SMF (OS1/2)

Max Distance: OM4: 400m and OS1/2: 10km

Connectors: SC, LC

Coaxial Connectors

RJ-11, BNC, F Connector, DB-9

Fiber Connectors

ST, SC, LC, MT-RJ

SFP/SFP+

Connector: LC

Speed: 1Gbit/s and 10Gbit/s

Cable Type: 10GBASE-SR or 10GBASE-LR

QSFP/QSFP+

Connector: LC

Speed: 4 × 1Gbit/s and 4 × 10Gbit/s

Cable Type: 40GBase Cables

PDU

·         Transmission units

·         Ethernet operates on a frame of data. Doesn’t care what’s inside.

·         IP operates on a packet of data, TCP or UDP

·         TCP segment/UDP datagram

Demarc Point

·         The point where you connect with the outside world, WAN provider, ISP

·         Can be used to establish a new WAN connection

·         Used everywhere

·         Central location in a building

·         You connect your CPE, customer premises

Baseband

A single frequency using the entire medium

Broadband

Transmission across multiple frequencies and different traffic types

Telnet

TCP/23

SSH (Secure Shell)

TCP/22

DNS (Domain Name System)

UDP/53 or TCP/53

SMTP (Simple Mail Transfer Protocol)

TCP/25 or TCP/587 (over TLS)

POP3 (Post Office Protocol v3)

TCP/110 or TCP/995 (over TLS)

IMAP4 (Internet Message Access Protocol v4)

TCP/143 or TCP/993 (over TLS)

SFTP (Secure File Transfer Protocol)

TCP/22

FTP (File Transfer Protocol)

TCP/20 or TCP/21

TFTP (Trivial File Transfer Protocol)

TCP/69

DHCP (Dynamic Host Configuration Protocol)

UDP/67 or UDP/68

HTTP (Hypertext Transfer Protocol)

TCP/80

HTTPS (Hypertext Transfer Protocol Secure)

TCP/443

Syslog

UDP/514

RDP (Remote Desktop Protocol)

TCP/3389

NTP (Network Time Protocol)

UDP/123

SIP (Session Initiation Protocol)

TCP/5060 or TCP/5061

SMB (Server Message Block)

TCP/445

LDAP (Lightweight Directory Access Protocol)

TCP/389

LDAPS (Lightweight Directory Access Protocol Secure)

TCP/636

Microsoft SQL Server

TCP/1443

Oracle SQL Net

TCP/1521

MySQL

TCP/3306

Start of Authority (SOA)

·         Describes the DNS zone details

·         Structure: Internet zone, Start of Authority, with name of zone, serial number, refresh/retry, expiry timeframes, caching duration/TTL

Address Records (A) (AAAA)

·         Defines the IP address of a host, most popular query

·         A records for IPv4

·         AAAA records for IPv6

CNAME

·         A name is an alias of another, canonical name

Service Records (SRV)

·         Find a specific service: Windows Domain Controller, Instant messager, VoIP controller

Mail Exchanger Record (MX)

·         Determines the host name for the mail server

·         Isn’t an IP, it’s a name

Name Server Records (NS)

·         List the name servers for a domain

·         NS records point to the name of the server

Pointer record (PTR)

·         The reverse of an A or AAAA record, send IP, get FQDN

·         Added to a reverse map zone file

Text Records (TXT)

·         Human-readable text information

Zone transfers

·         Replicate a DNS database: The primary DNS server has the primary copy of the zone information

·         Synchronize to a secondary server, provide redundancy

·         Triggered by referencing the serial number, if serial number increases, must’ve been a change

·         Full zone transfers can be a security risk, attacks can use the data as reconnaissance

Three-tier architecture

·         Core: The “center” of the network, web servers, databases, applications

·         Distribution: A midpoint between the core and the users, communication between access switches

·         Access: Where the users connect, end stations, printers

SDN (Software Defined Networking)

·         Split the functions into separate logical units

·         Extend the functionality and management of a single device

·         Perfect for the cloud

·         Infrastructure layer / Data plane: Process the network frames/packets, forwarding, trunking, encryption, NAT

·         Control layer / Control plane: Routing tables, session tables, NAT tables, Dynamic routing protocol updates

·         Application layer / Management plane: Configure and manage the device

Spine and Leaf Architecture

·         Each leaf switch connects to each spine switch

·         Leaf switches do not connect to each other

·         Top-of-rack switching: Each leaf is on the “top” of a physical network rack

·         Advantages: Simple cabling, redundant, fast

·         Disadvantages: Additional switches may be costly

SAN (Storage Area Network)

·         Looks and feels like a local storage device

·         Block-level access (large file, need to change one small piece, only change the small block)

·         Very efficient reading and writing

·         Requires a lot of bandwidth

·         Usually has its on dedicated network

Fibre Channel (FC)

·         A specialized high-speed topology

·         Connect servers to storage

·         2,4,8,16 gigabit/s rates

·         Supported over both fiber and copper

·         Servers and storage connect to a Fibre Channel switch

Fibre Channel over Ethernet (FCoE)

·         Use Fibre Channel over an Ethernet network

·         No special networking hardware needed, usually integrates with an existing Fibre Channel infrastructure

·         Not routable

iSCSI (Internet Small Computer Systems Interface)

·         Send SCSI commands over an IP network

·         Makes a remote disk look and operate like a local disk

·         Can be managed quite well in software

Infrastructure as a Service (IaaS)

·         Sometimes called Hardware as a Service (HaaS)

·         Outsource your equipment/hiring a third party to provide the hardware

·         Still responsible for the management and security

·         Data is out there, but more within your control

·         Web server providers

Software as a Service (SaaS)

·         On-demand software

·         No local installation

·         Central management of data and applications, data is out there, third-party responsible for it

·         A complete application offering

·         Ex: Google Mail, Office 365

Platform as a Service (PaaS)

·         No servers, no software, no maintenance team, no HVAC

·         Someone else handles the platform, you handle the development

·         Don’t have direct control of the data, people, or infrastructure, trained security professionals are watching your stuff

·         Put the building blocks together

Desktop as a Service (DaaS)

·         Basic application usage

·         Applications run on a remote server, VDI (Virtual Desktop Infrastructure)

·         Local device is a keyboard, mouse, and screen

·         Minimal OS on the client, no huge memory or CPU needs

·         Network connectivity: Big network requirement

·         Ex: Amazon WorkSpaces

SCADA / ICS

    Pc manages equipment: Power generation, refining, manufacturing equipment, facilities, industrial, energy, logistics

·         Distributed control systems: Real-time info, system control

·         Requires extensive segmentation, no access from the outside

PBX (Private Branch Exchange)

The phone switch, connects to phone provider network, analog telephone lines to each desk

VoIP PBX

Integrate VoIP devices with a corporate phone switch

Voice gateway

Convert between VoIP protocols and traditional PSTN protocols, often built-in to the VoIP PBX

Power over Ethernet (PoE)

·         Power provided on an Ethernet cable

·         Phones, cameras, wireless access points

·         Power provided at the switch

·         Built-in power = Endspans

·         In-line power injector = Midspans

·         Mode A: Power on the data pairs

·         Mode B: Power on the spare pairs

·         POE: IEEE 802.3af, original PoE standard, 15.4 watts DC power, max current 350 mA

·         POE+: IEEE 802.3at, updated PoE standard, 25.5 watts DC power, max current 600 mA

VLANs

·         VLAN assignment: Each device port should be assigned a VLAN

·         Trunking: Connecting switches together, Multiple VLANs in a single link

·         Tagged and untagged VLANs

·         A non-tagged frame is on the default VLAN (also called a native VLAN)

·         Trunk ports will tag the outgoing frames, untag the incoming frames

Straight-Through Cables

·         Patch cables

·         Most common Ethernet Cable

·         Connect workstations to network devices

·         Connects unlike devices

Cross-Over Cables

·         Connect MDI to MDI

·         Connect MDI-X to MDI-X

·         Connects like devices

Rollover Cable

·         A standard for RJ-45 to serial communication

·         A laptop to console connection

GSM

·         90% of the market

·         Move your SIM card from phone to phone

CDMA

·         Everyone communicates at the same time, each call uses a different code, the codes are used to filter each call on the receiving side

3G

·         Upgraded data connectivity over 2G, improved speeds, usually 7 Mbit/s

·         Bandwidth improvements allowed functionality, GPS, mobile television, video on demand, video conferencing

4G

·         Long Term Evolution (LTE)

·         Converged standard (GSM and CDMA)

·         Supports 150 Mbit/s

·         LTE Advanced (LTE-A), download rates to 300 Mbit/s

5G

·         Significant performance improvements

·         Higher frequencies

·         Slower speeds 100-900 Mbit/s, higher speeds 10 Gbit/s

·         Significant IoT impact, bandwidth less of a constraint, large data transfers, faster monitoring, additional cloud processing

Netflow

·         Gather traffic statistic from all traffic flows, shared communication between devices

·         Probe and collector: Probe watches network communication, summary records are sent to the collector

·         Usually a separate reporting app

System Life Cycle

·         Managing asset disposal: Desktops, laptops, tablets, mobile devices

·         Disposal can be a legal issue, some information can’t be destroyed

·         Don’t want critical information in the trash (dumpster diving)

SLA (Service Level Agreement)

Minimum terms for services provided, uptime, response time agreement, common between customers and service providers

Memorandum of Understanding (MOU)

Both sides agree on the contents of the memorandum, usually includes statements of confidentiality, informal letter of intent, not a signed contract

Non-disclosure Agreement (NDA)

·         Confidentiality agreement between parties, information should not be disclosed

·         Protects confidential information, trade secrets, business activities, anything else listed

·         Unilateral or bilateral

·         Formal contract, must be signed

Acceptable Use Policy (AUP)

·         Detailed documentation, rules of behavior

·         Covers many topics: Internet use, telephones, computers, mobile devices

·         Used by an organization to limit legal liability

Main Distribution Frame (MDF)

·         Central point of the network, usually in a data center

·         Termination point for WAN links, Connects inside to the outside/demarc

·         Good test point

·         Often the data center