• Hosts meant for end users, like desktops, laptops, and tablets, normally get their configuration via the ==Dynamic Host Configuration Protocol (DHCP).==

  • To connect a host to a network it needs a valid IP address and a subnet mask.

    • If it needs to communicate with hosts beyond the local network, it needs a default gateway. Knowing the addresses of your DNS servers is a definite plus.
  • IPv4 address is a 32-bit number assigned to a specific network device, globally unique to network.

  • Rather than a single large number, IP addresses are usually expressed as four eight-bit decimal numbers, such as 203.0.113.1. This “dotted quad notation is easier.

  • A block of IP addresses is called a network or subnet. Organization’s Internet Service Provider (ISP) allocates a subnet to the organization.

    • Strictly speaking, all the IP addresses on the Internet are one network. Every smaller allocation is a subnet, or a subnet of a subnet.
  • Hosts can only communicate directly with hosts on the same IP subnet. To communicate with hosts on a different network, they must go through a router—even if they’re on the same Ethernet.

    • Each subnet contains a number of addresses equal to a power of 2.