CompTIA Part 1 Study Set (Networking/Internet/Virtualization)

Plenum ratings

based on the cables ability to resist fire - PVC (non-plenum): worst quality, very cheap - Riser: intermediate quality, designed for cables running between floors - Plenum: much more resistant to fire

Two types of ways to propagate the light signal in fiber optic

o Multimode: used LED, tend to see in network environment o Singlemode: uses lasers

- Highly directional

o Yagi: Signal: known as a fernel lens is really good for shooting long distances Would usually have two highly directional antennae's pointing back at eachother o Parabolic: alternative for highly directional antennae with very long throws

Automatic Private IP addressing (APIPA)

on most OS systems that act as a fallback in case you can't find a DHCP server - Will always give a 169.254.X.X address o Class B, last two digits spun up randomly - Can't get on the internet, can only use LAN - An IP address from a DHCP server in always attempted to be spun up first, then APIPA is a fallback - If you can connect locally but can't connect to internet, make sure to use ipconfig and see if you have an APIPA address. If your APIPA, attempt to reconnect to the DHCP server

Omnidirectional Antennas

one piece of metal that sticks up (like seen on a car) o Radiation pattern looks like a big, fuzzy ball signal propogation. The more power put to antenna, the larger the fuzzy, ball signal propagation gets o Dipole: two omni directional antennas pointing exactly opposite of eachother Create a very useful signal type for wireless, looks like a stepped on donut - Patch: always have a flat look, radiation signal is a big fuzzy wall, but just half of one (ex: your on a wall and only want it to go one way)

Twisted pair wires come in ...

orange, green, blue, and brown. Important for crimping in a very specific order

Local area network (LAN)

originally, it connected all the devices by wire to a hub. In today's world, a wireless access point (WAP) is used and all devices talk on the same frequency

UDP and ICMP

other type of protocol that data is sent on rarely - UDP: connectionless protocol, no handshake created - ICMP: connectionless single-packet protocol, does little things like ping command for example

TCP segment/ UDP datagram

part of ethernet frame that includes the TCP/UDP info

Simple Network Management Protocol (SNMP)

powerful tool used by network administrators to locate and see advanced metrics of discovered devices

DOCSIS

alternative networking type used for cable modems

In order to get a computer on the internet, you need to

- Give it an IP address - Give it a subnet mask - Give it a default gateway

DNS servers store lots of records

- A record: regular stuff like www and IP address - MX record: used by mail servers - Cname: can give IP addresses different names - Used to be able to query the server, but got locked down because it was abused

Special IP addresses

- Class D- Multicast: used in presentation stuff like live video presentations - Class E- Reserved: never used

IP address details

- Contain 4 characters which go from 0-255 - Will have 3 dots in between them - Never end with a 0 or 255. A 0 at the end identifies an entire LAN

Every ethernet frame has 4 parts (in order)

- Destination MAC address - Source MAC address - Data - Frame check sequence (FCS): a checker for the data to make sure when it comes it that it is in good order

Antennas

how the signal travels

Protocol data unit (PDU)

the way that IP packets are organized

A _____ is some kind of program used to access a ______

- client, server - The web browser is a web client used to connect to a server, which is a computer running server software (ex: ISS, Apache) - The server is a computer that is running software that is waiting for a client to send a request and stored on that server are the web pages that will then be handed to the client - Everything on the internet is a client and a server

Plenum

space between the drop ceiling (or floor) and actual ceiling where cables go

Three types of port numbers - Well-known ports

0-1023, applications like the Web, Secure Web, etc. - Registered ports: 1024-49151, people who came after well-known ports but still want own port (ex: steam games) - Dynamic/Ephemeral ports: 49152-65535, second port number on system is always an ephemeral port number

IP addresses have four octets between ____

0-255

Back in 80s-90s, _____________ attempted to create a US nationwide WAN between military posts and universities across the US. Was called ________ of the internet. It was a form of _______________.

ARPANET, Tier 1, aggregation

Network troubleshooting

Q: No connectivity A: Are you physically connected? Check cable. Check your IP addressing, use ping . If you have static addresses, there is a possibility you have IP conflicts (two devices with same address). If this is the case, the OS with put up a big IP conflict warning. Q: Limited connectivity (some stuff you can get to, some stuff you cant) A: Likely to do with DHCP server. Watch for APIPA addresses (169.254.x.x). Could potentially also be a rouge DHCP server if the network ID has changed, which is a serious error that somebody else has plugged in a DHCP server in and is passing out bad info. You need to trace and find whoever is doing that. Q: Intermittent connectivity A: Rare in a wired network. Usually some kind of problem with the cable itself like interference problems and need to move the cable. Q: Unavailable resources A: First check if you can get to the system itself and try pinging it. Otherwise you may have a problem with the resource itself, and may be because NTFS or NSP unplugged you from a resource Q: Slow transfer speeds A: Usually a wireless issue, but it can show up. First check task manager and see how hard the network card is being used. If it's really spiking up, you need to go through the processes that are eating up the network bandwidth and take them out. (Could be something like downloading a big update in the background, may be where QoS settings could be handy)

Fox (tone generator) and hound (tone probe)

Used to locate cables (generally homeless cables) - Fox makes the noise, hound locates the tone

If you're handed a switch and the connected devices aren't able to communicate with eachother, there's a good chance there are _______

VLAN configuration issues

Wide area network (WAN)

a network that connects multiple LANs together

Troubleshoot (windows)

a quick way to test your network - Right click wi-fi icon

Ad Hoc Mode

a rare type of wireless connection with no WAP. Just have a bunch of NICs and one specific NIC is treated like a WAP

Hub

a repeater that repeats frames back to all connected devices- The devices who see the destination MAC address is not theirs ignore the incoming frame- Causes problem because all connected devices have to share the same hub bandwidth (throughput) which causes major slowdowns

Local Management

a router setting that can change how to access the router web server (ex: from a specific computer) - Using remote management is a very unsecure thing to do because anyone could access it given the right info

Wireless Access Point

a bridge between an ethernet network and a IEEE 802.11 network - Antennae are a clue the device in wireless - True WAPs only have one ethernet connection

Ipconfig /renew

a command that connects you to a DHCP server

Ipconfig /all

a command that gives network information

Ipconfig /release

a command that releases you from a DHCP server

Console port

a serial port that uses the RS32 language and a DB9 connector - The blue cable used to connect is called a Yost/ Rollover cable and were made famous by Cisco - Connects to a device and uses a terminal device (often through Putty) in order to configure (talks with CiscoIOS) SOHO (small office/ home office) Environment: the primary way to connect to routers is through a web interface - Much more expensive - Probably passes out a DHCP range - Also has a default username and password (which should be changed for convenience) - Setting up: o Use ipconfig to make sure you're getting a DHCP address o If getting a APIPA address, that means it is not handing out DHCP and you need to check user manual to find the default address and set a static IP address to match the range o THE DEFUALT GATEWAY IS YOUR ROUTER o Type your default gateway IP address into a browser and you will connect to the config

Dynamic Host Configuration Protocol (DHCP)

a server that automatically assigns IP addresses when they are booted - Home routers often act as one - Computers within your LAN, so sometimes they can go down

Protocol

a set of rules that allow different things to work together

DHCP Reservation

a setting that gives a specific device a certain IP address that is not from the default pool - Not very practical

Lease Time

a setting under the DHCP server that changes the time IP addresses are leased to devices. Most people like longer leases (>2 hours) for desktops and shorter leases (<2 hours) for mobile devices

Hexadecimal

a shorthand nomenclature used to represent long strings of binary - Replace a 4 character string of binary with one character - A base 16 counting system because there are 16 possible combinations for a binary 4 character string - The letter 10 is replaced with the letter A and so on - Can represent any string of 4 1s and 0s with 1-9 and A-F - (h is just to represent hexadecimal) - Every 1 hexadecimal value equals 4 binary values - Ex: a MAC address which has 12 hexadecimal values is a 48-bit address (12*4 = 48)

Switch

a smart repeater much better than a hub, it stores the MAC addresses of all connected devices and creates a direct link from one device to another when they are communicating - Almost always used over hubs in modern day - Only sends data out to proper destination based on MAC address - Provide full bandwidth for all nodes - Switches learn MAC addresses by simply watching the frames

Resource Monitor

a tool to view and manage connections on Windows - Just because you open one webpage doesn't mean you will get just one connection. Things like ads, Javascript applications, backgrounds, will create new connections.

Quality of Service (QoS)

a toolset that allows you to meter how much bandwidth things get - Can give a certain IP address or MAC address or assert certain ports to have more or less bandwidth - Need to know your uplink and downlink speeds (which depends based on your provider and plan) - Can configure by port number to designate certain things (ex: like a specific steam game for example) to have more or less bandwidth

Wireless Network Card

a type of NIC (Network Interface Controller) - For laptops, antenna for network card is in the monitor itself - For mobile devices, network cards are built in and antenna spans the entire case

Structured cabling

a way of properly organizing cables - Usually stored in a room, which is called the Main Distribution Frame (MDF) - Racks are very standard. Height is used in convention called a "u" - Horizontal Run: run through wall outlets. Plugs into back of rack part called a patch panel o Most important part of structured cabling - Boot: rubber chunk at the end of ethernet cables - The longest horiztonal run you can have is 90 meters

IEEE 802.11

a wireless standard that is the primary way most of our wireless devices talk - Has different standards, but generally same principles - Works in two modes: infrastructure and ad hoc mode

Transmission Control Protocol/Internet Protocol (TCP/IP)

almost all the data send on the internet uses this protocol - TCP: connection-oriented protocol, creates a handshake were computer greet each other

Static IP Address

are made by manually typing in by hand, the IP address, subnet mask, and default gateway - These are done by the administrator setting up the network - Would require the need to change them every time you moved networks

Port Security

can make the switch memorize the assigned MAC addresses of the plugged in system and turn the port off if other addresses try to connect to the specific port or send a message

ping -t

command that continually pings. Very useful for checking networks - Linux and Mac ping continually automatically - Use control+c to stop pinging

Coaxial cable

connectors are axial, has big center piece, insulator, and outer cladding used as a signal tool -o All used F-type connectors, which are a threaded connector

TIA 568A/TIA 568B

crimping orientation standard - - The A in 568A stands for alphabetical (green before orange) - Blue always in 4-5 and brown always in 7-8

Ethernet frames now include a _________ and _______ which allows the device to jump from LAN to LAN

destination IP, source IP

Routers

devices that filter and forward traffic based on IP addresses - - Routers have a ranges of shapes and sizes - Routers are often combined with other devices like switches or WAP

Cat (category) ratings

different types of unsheilded twisted pair designed to carry different amounts of information. Include: - CAT 5: designed for 100 Mbps network - CAT 5e: works for 1 Gbps - CAT 6: works for 1 Gbps up to 100 meters and 10 Gbps up to 55 meters - Cat 6a: works for 10 Gbps at 100 meter segments

Nslookup

dns command tool built into most OS - Used to give too much info so most servers have locked down against this tool except basic info - Can type in websites to check if they are functioning properly - If you get a timeout, you know that the DNS server is not functioning properly

Solid core

each wire is an individual piece of copper that carries electricity very well - Used in wall and horizontal runs because it is good for long runs and is not exposed to frequent bending

IPv4

early version of IP addressing that was used to build the Internet - More advanced version is IPv6

If you install a Windows system, it will either be a member of a ___________ or a member of an ____________________

workgroup, active directory domain

Stranded

for patch cables themselves. Each of 8 wires is stranded

Port Number

get you to right application on the computer - Range from 0-65535 - Always have a source and a destination port number - Servers "listen" on port numbers - Servers can listen on multiple ports - Each window on a browser gets its own port number that is spun up automatically by the OS

Fully Qualified Domain Name (FQDN)

go through a registration process, get a unique name, assign it to a DNS server, add things to it - Have a 256-character limit (max of 255 including dots)

Homegroup

idea was in-between security of domain and convenience of workgroup

IPv6

improved version of IPv4 because they ran out of addresses - Have 8 groups separated by 8 colons - (number of IPv6 addresses) - There is a shorthand the compresses a group with a lead 0 into just "0" and a triple group of 0's into a double colon - Today's systems have a minimum of 2 IP addresses o Link-local address: always written as fe80:0000:0000:0000: [last half auto generated], used for local connections o Internet address (global unicast address): brought from router, used for the Internet - Very secure

Crossover cable

include one side as T568A and T568B - Can be used to plug two computers directly into eachother where they can communicate (usually)

Managed switch

is a switch that has been assigned an IP address that can allow for VLANs and other features. It's firmware interface is capable of managing VLANs, port security, and more features.

Routing Table

tells the router where to send stuff o All routing tables have a default gateway, meaning if you don't specifically state the network ID sent it out - More secure and automated organization - Was powerful but was eventually dumped by Windows

Channels

made to be more user friendly, each channel takes a piece of the band that can be tuned to by a WAP.

Universal Plug and Play (UPnP)

makes your device "noisy" to make it more visible when your networking (rather than just depending on Windows) - Used in routers and switches

Workgroup

most basic type of networking organization - No security, no central administration - Works just fine for small networks - Default and free

Infrastructure Mode

most common way we use 802.11. Uses WAPs and NICs

Ethernet

most popular type of networking used today - States you can only send your data in discrete chunks of 1500 bytes (called a frame). The OS has the smarts to take the data apart and put it together - Attempts to solve the problem of one system hogging up all the connection in a LAN or WAP and not letting other systems intercept the data

Domain

need a Windows server system - Active Directory Domains are set up, and provide excellent security, substantial central administration, very powerful, and very expensive - Used mainly for enterprise environments - Pay for through expertise and money

Shielded twisted pair

provide a lot of robust protection for cable

RG ratings

rating system for coaxial cables o RG-58: only type commonly used in networking world, very thin type of coaxial cable, used a connector called BNC, which is not threaded o RG-59: used for both video and networking o RG-6: used for both video and netowrking

Loopback 1P address

refers to your own system - Used to be a good way to test your computer - Is always 127.0.0.1 ping 127.0.0.1: a command that sends a ping packet (a single ping) to a particular IP address o Can be used to check that network card it running

Router

sensitive to different LANs and able to police traffic across the LAN networks to create a WAN - Differentiate not only different specific computers, but specific LANs

Service Set Identifier (SSID)

set up by WAP, naming convention for connecting wirelessly

Rule of Ethernet

that states you should not put over 1024 computers on a single switch (or daisy-chained switches) - In reality 30-40 computers is the standard maximum size - Switch becomes very overloaded

NAT (Network Address Translation)

solves the IPv4 problem - Makes it so not every computer actually has to have a completely unique ID - Provide that all devices in your LAN use a private IP address. Because private IP addresses cannot go across routers, the gateway router takes off the private IP address and inserts a new legitimate public address (while documenting the private address) and then puts it back on once the packet comes back. - Downside is that is slows things down a little bit and that anything in the LAN is invisible to the Internet - Public IP on WAN, private IP on LAN

Subnet Mask

something that checks to see if the IP address is in the LAN or outside - If the call is outside the LAN, it sends it to the default gateway (aka the router) - A 225 in a subnet mask means that every octet is part of the network address - Are generally 255.255.255.0

Domain Name System (DNS)

take fully qualified domain names and translates what IP address is associated with that - Replaced the host file, which was the old way of storing IP addresses and domain names - Root servers: clusters of very powerful DNS servers around the world o Control the domain name "." o First level domains control things like ".com" ".edu" ".gov" o Second level domains control things like "totalsem.com" "google.com" - The DNS server in communication with the computer locates the closet root server based on geography - The little message on screen stating "waiting for..." is the DNS server at work - Once your computer has used the DNS server to visit a site for the first time, the computer and DNS server will both cache a copy of the IP address for a certain amount of time

Virtual Local Area Network (VLAN)

takes one physical switch and electronically turns into two or more switches - Allows you to put certain things on different networks without having to buy a new switch - Very popular

Netbios/netbt

the Windows naming convention for computers - Each computer will have a name, which is important for the human way to recognize what the computer is - Usually setup during installation - Predates DNS and most of the Internet

IP addressing

the form of logical addressing used o Ex: 192.168.4.100 o Every device inside a LAN gets a unique address o The first three numbers are the same in a LAN, and the last three numbers have to be unique o The router itself has its own address (usually ends with a .1) for the connected LAN. It also has another address used to connected to a separate LAN

Network and Sharing Center

the place on Windows that deals with everything you need regarding network information

Industrial, Scientific, and Medical (ISM) radio bands

the radio bands utilized for wireless signals - A band is a range of radio frequencies, so different WAPs can use different ranges too avoid overuse of one range

Domain Name System (DNS)

translates domain names into IP addresses and points your device in the right direction - Get you to the computer

Media access control (MAC) address

uniquely identifies every device on a wireless system - A 48-bit address that is always manifested as 12 hexadecimal characters - Every network card gets a unique MAC address - OEM ID: first 6 characters, issued by the issuing body of the internet. Other 6 characters can be spun up however desired - Can type in "ipconfig /all" into command prompt to see MAC address (under physical address) alongside other network information

Private IP address

used for private networks - Have three sets: o (Any IP address that starts with 10, 172.16 - 172.31, or 192.168)

Crimps

used to connect cables - Come with their own rating systems, so have to double check they match with the cat rating systems - Use a cable crimper/cutter tool - Come in RJ-11 and RJ-45 forms

Logical addressing

used to identify each device under a specific LAN and communicate that to routers to achieve a WAN. Determine local vs. remote traffic - Not a physical address like a MAC address, must be typed in

110 punchdown tool

used to punch cables into the patch panel - Always make sure larger tip is on the outside - Make sure to follow patterns on patch panel

Cable tester

used to test for continuity and orientation of cables

Fiber optic (fiber) cable

uses light instead of electricity (electrical pulses) - Extremely popular with fast Ethernet situations - Usually come in a pair of wires. One for sending and one for receiving

Time Domain Reflectometer (TDR)

uses speed of light to detect how long a cable is

Link Layer Discovery Protocol (LLDP)

what Windows uses and is on by default to help with network device identification

Straight-through cable

when you have the cable wired correctly, same on both sides - Check for continuity and wire orientation

Twisted Pair

without its shielding it is called unshielded twisted pair (UTP) - Most networks used twisted pair cabling - Twists help propagate the signal better - Commonly have 4 wires (so 8 individual) - Generally run at about 100 meters - Has had many different versions - Utilize RJ-11 and RJ-45