* THIS GUIDE IS A Work In Progress *

Home Networking

Router, Modem, Switch, Port
Wifi - Wired - Radio - Microwave
Lan - Wan
cellular - 3 vs 4 vs 5ghz
phiber copper

Lines

cat5e/6 - punch downs - tracing
rj45 - termination a-vs-b etc
toning

Networks

Router and Gateway or Default Gateway are all the same thing
a router seperates two different networks
inside part of router - (wired = 1 mac)
outside part of router (the internet = 2nd mac)

mac address is hardcoded in hexdecimal- the format is made with 24 bits (6 values) -
who made it (the last 24 bits (6 values) = serial number of device.
ethernet addressing is mac address

DLL (not to be confused with a Dynamic Link Library - which basically function similiarly to java in web design.
They contain both code that can be accessed by multiple applications at once as well as links to other resources)

a frame is a data link layer component.
the data link layer is responsible for local network communication
passing information and data in the form of frames through the local network.

NLL
network interface layer
network interface cards - take physical digital signal and convert it into a frame DLL (data link layer)
(signal to 1's and zeros to frame)
(frame to 1's and zeros to signal)

  • mac = device "compuer"
  • ip addy = device global address
  • subnet mask = for separating different local network traffic
  • default gateway = router

    • Data Link Layer Encapsulation

    in order to move a packet with the ip addresses in it
    it must be placed inside a frame before it can be sent over a network
    the frame can only move on the local network
    it is sent to the router (default gateway)
    the router discards the frame and places the packet inside a new frame before sending it across the internet
    this repacking of packets happens each time the packet reaches a router.

    255.255.255.0
    255.255.255 = network .0 - host

    network = group of devices
    host = single device

    each ip network is unique to the network.

    a cross over cable allows two computers to communicate with one another
    (closed non internet network)

    if you change the ip network of a device it will then be on the network.

    working example:
    device one 192.168.104.1
    device two 192.168.104.2

    non working example:
    device one 192.168.102.1
    device two 192.168.104.2

    IPV6 is generally converted on IP4 networks through "network adapters" tunneling.
    cmd -? ipconfig will show tunneling adapters

    packet inter net gropper (ping)
    ping 192.168.104.2
    - unreachable reasons "turned off" - "bad ip" "broken ethernet" - "broken router"

    ipconfig /all - lol (for mac address) which is the same as the physical address

    you cannot have two devices on the same local network with different global ip addresses that just doesnt work
    the outside global network is determined by the gateway ip

    Binary to Hexadecimal

    base 10 - numbering system for money, fingers on our hands, etc. (how we count) 0-1-2-3-4-5-6-7-8-9 - deeply engraved in our brains
    binary - (numbering system for computers, on vs off) 0-1

    binary counting 1-2-4-8-16-32-64-128

    0
    1
    01
    10
    11
    100 4s
    101
    110
    111
    1000 8s

    converting binary to decimal

    512 256 128 64 32 16 8 4 2 1
    1x the place holder and add up all values = decimal.

    for instance A from ascii is 0100 0001 in binary

    128 64 32 16 8 4 2 1 - place
    0 1 0 0 0 0 0 1 - binary
    'xs the placeholder
    0 64 0 0 0 0 0 1 - sum

    add 64 + 1 = 65

    converting decimal to binary
    can I subtract and end up with 0 or a positive number?

    210
    128 64 32 16 8 4 2 1 - place

    can I subtract 128 from 210? y = 82
    can I subtract 64 from 82? y = 18
    can I subtract 32 from 18? n =
    can I subtract 16 from 18? y = 2
    can I subtract 8 from 2? n =
    can I subtract 4 from 2? n =
    can I subtract 2 from 2? y = 0
    can I subtract 0 from 0? n =

    if yes = 1 if no - 0

    11010010 = 210

    hexadecimal is base 16

    every hexadecimal value can always be converted to 4 binary bits (binary is a code of 8 bits or two sets of 4 bits so each hex value when converted to binary is two 4 bit values)

    10-11-12-13-14-15 - place
    0-1-2-3-4-5-6-7-8-9-A-B-C-D-E-F

    example: hex 1A5F

    1 A 5 F
    0001 1010 0101 1111 - binary
    8421 8421 8421 8421 - place holder
    1 10 5 15 - place value in hexadecimal

    IP and Subnets

    203.0.113.10
    203.0.113 = network portion - network name
    .10 = host portion - machine name

    each number is an octet and each contain 8 bits (4 sets of 8 bits)

    203 0 113 10
    11001011 00000000 01110001 00001010
    (the subnet mask was hacked/add/edited to IPV5 after 1995)
    it added a separate number to all IP4 addresses which is called the subnet mask
    it basically adds 1's to network portions and 0 to hosts.
    11111111 11111111 1111111 00000000
    225 255 255 0

    but with current classless IP4 we can change the network portion to any part of our network.
    you can change the network portion to host portion ration by changing the subnet mask
    for example you can change the number to 255 200 120 0 which would change the amount of host (the last numbers).

    understanding pre-1995 ip4
    classful ip addressing was split into 4 potions (no subnet mask just the address deciding the ration of net to host)
    the range is what is determining the portions
    class A 0.0.0.0 - 127.255.255.255 8bit net 24bit host
    class B 128.0.0.0 - 191.255.255.255 16 net 16 host
    class C 192.0.0.0 -223.255.255.255 24bit net - 8 bit host
    class D 224.0.0.0 - 239.255.255.255 - network portion - this is multi-cast - all network like a bridge

    What kind of IP address is this?
    break it into binary and look at the host portion of the ip address

    network network network host
    203 0 113 10
    11001011 00000000 01110001 00001010 binary ip addy (look here)
    11111111 11111111 1111111 00000000 subnet mask
    225 255 255 0

    if the host is all binary zeros then it is a network address
    if it's all 1's in the host portion it is a broadcast IP address and cannot be assigned to any devices.
    if host is a mix of zeroes and ones it is a host address that can be assigned

    for example most network ip addresses end in zero but

    10.128.224.64
    255.255.255.224 - this mask has changed the net to host ratio of the ip
    00001010 10000000 11100000 010|00000 - the last 5 are now the host which are all zeros making this a network IP.
    11111111 11111111 11111111 111|00000

    another example - most host addresses do not end in zero but

    10.128.225.0
    255.255.254.0
    00001010 10000000 1110000|1 00000000 the host portion contains a 1 making this a device/host ip that can be assigned.
    11111111 11111111 1111111|0 00000000

    private ip ranges
    (can only be on internal networks)

    10.0.0.0 10.255.255.255
    172.16.0.0 172.31.255.255
    192.168.0.0 192.168.255.255

    127.0.0.1 = loop back address or home
    01111111.00000000.00000000.00000001

    Subnet Calculator

    example

    if 2bits = a network(2 to the number of bits) - each network needs a router
    unless its a virtual network.
    for hosts - 2

    (if there are 5 bits in the network portion - you can make 32 unique networks)

    bits networks hosts
    0 1 0
    1 2 0
    2 4 2
    3 8 6 - you need 3 bits for 8 networks
    4 16 14 - if you need 10 networks you need 4 bits
    5 32 30
    6 64 62
    7 128 126 - 7 bits only gives us 126 hosts
    8 256 254
    9 512 510
    10 1024 1022
    11 2048 2046
    12 4096 4094
    13 8192 8190

    this is helpful when deciding how many bits you need in a subnet mask

    VLSM - Variable Length Subnet Masking
    basically means different subnet lengths to allow for different hosts amounts
    as required. so if two subnets need different amount of pcs (available ips)
    then different subnet numbers should be applied.