Networking Basic Concepts

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Ipconfig
  1. ipconfig/ifconfig - is to know your IP address in windows and linux.
    1. IPV4 : -192.168.12.11
    2. IPV6 : -fe80::ccae:baba:6fd8:5551%9
  2. eight 1s and 0s in each part of the IP address.
  3. due to the limitations of IPv4 address, IPv6 introduced.
    1. IPv4 got introduced in 1980s on that time nobody thought to have these many IP address on computers. 
    2. When they thought about the problem with the extensive use of the computers then developed IPv6.
    3. IPv4 addresses were 2 power 32 only because it is 32 bit addresses.
    4. IPV6 address were 2 power 128 because these are 128 bit addresses.
  4. NAT : -
    1. when we have a home network with 15 devices connected to internet then all 15 devices will not get addresses from IPv4.
    2. only the router will have the main address from IPv4 and 15 devices will have private IP assigned by router.
      1. requests going from 15 devices to router 
      2. router will put its IP and send it to internet then servers.
      3. router receives the response back and serves required response to related request with the help of NAT (network address translation)

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MAC Address

  1. MAC addresses/physical address uses at layer 2. - switching
  2. IP addresses are used at layer 3. - routing
  3. Media access control - MAC 
  4. use ipconfig/ifconfig to check.
    1. 00:0c:29:0a:42:05
    2. first three payer of above MAC address = identifier.
      1. copy those and find in MAC lookup, we will be able to find out.

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TCP vs UDP
  1. Transmission control Protocol
    1. Connection Oriented
    2. High reliability.
    3. HTTP, HTTPS, SSH, FTP.
    4. 3 WAY handshake
      1. SYN >> SYN ACK >> ACK.
      2. hello to neighbor = syn
      3. neigbor hello back = syn ACK
      4. Acknowledge for good to go = ACK
    5. Common Ports: -
      1. ftp 21
      2. ssh 22
      3. telnet 23
      4. smtp 25
      5. dns 53
      6. http 80
      7. https 443
      8. pop3 110
      9. smb 139 , 445
      10. imap 143
  2. User datagram protocol
    1. Connection less
    2. less reliable.
    3. video streamimg, VOIP, DNS
    4. Common ports
      1. DNS 53
      2. dhcp 67, 68
      3. tftp 69
      4. snmp 161


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OSI Model
  1. P (Please)       - PHYSICAL           - data cables, cat6 (LAN cables)
  2. D ( Do )          - DATA                  - switching, MAC address
  3. N ( Not )        - NETWORK          - IP addresses, routing 
  4. T ( Throw)      - TRANSPORT       - TCP, UDP
  5. S ( Sausage)   - SESSION            - session management
  6. P ( Pizza)        - PRESENTATION  - WMV, jpeg, HTML
  7. A ( Away)       - APPLICATION     - HTTP, SMTP, FTP

All People Seems To Need Data Processing

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Subnetting
  1. Subnet - 255.255.255.0
  2. eight bits in every octet, like IP address


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