IPv4 Addresses

Networking with IPv4
  • IP Address, e.g., 192.168.1.165
    • Every device needs a unique IP address
  • Subnet mask, e.g., 255.255.255.0
    • Used by the local device to determine what subnet it's on
    • The subnet mask isn't (usually) transmitted across the network
    • You'll ask for the subnet mask all the time
    • What's the subnet mask of this network?
  • Default gateway, e.g., 192.168.1.1
    • The router that allows you to communicate outside of your local subnet
    • The default gateway must be an IP address on the local subnet
Special IPv4 addresses
  • Loopback address
    • An address to yourself
    • Ranges from 127.0.0.1 through 127.255.255.254
    • An easy way to self-reference (ping 127.0.0.1)
  • Reserved addresses
    • Set aside for future use or testing
    • 240.0.0.1 through 254.255.255.254
  • Virtual IP addresses (VIP)
    • Not associated with a physical network adapter
    • Virtual machine, internal router address

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