IP Addressing

public

Public IP address are IP addresses that haven't been reserved for private use by Internet standards groups. They're recognizable on public networks, such as the Internet. The Internet Assigned Numbers Authority, or IANA, manages the distribution of public IP addresses. Public IP addresses must be unique per host in order to be valid, as they are routed over public networks.

Class C

Class C IP addresses use the first three octets of an IP address for the network ID. The last octet is used for host information. Class C networks have the fewest available hosts, as only one octet is used for the host ID. Class C includes addresses in the range 192.0.0.0 to 223.255.255.255

Class D

Class D IP addresses are reserved for multicasting. Class D includes addresses in the range 224.0.0.0 to 239.255.255.255.

Class E

Class E IP addresses are reserved for experimental use. Class E includes addresses in the range 240.0.0.0 to 255.255.255.255.

multicast addresses

Data sent to a multicast address is transmitted from one node to a select group of nodes.

unicast addresses

Data sent to a unicast address is transmitted from one node to another.

anycast addresses

Data sent to an anycast address is transmitted from one node to the nearest node in a group of receivers.

APIPA

APIPA addresses are a feature in Windows Dynamic Host Configuration Protocol, or DHCP. Class B IP addresses in the 169.254.0.0 range are assigned to clients when a DHCP server is unavailable. APIPA addresses are intended for small and non-routable networks. As soon as a DHCP server is available, an APIPA address is replaced by an address assigned by that server.

Class A

Class A IP addresses use the first octet to denote the network ID. The remaining 24 bits, held within the last three octets, contain the host information. By definition, the first bit in Class A addresses is always set to zero. This means that the value of the first octet in a Class A address can never be higher than 127 - a value of 128 would mean the initial bit would be set to one, not zero. Class A includes addresses in the range 0.0.0.0 to 127.255.255.255.

Class B

Class B IP addresses use the first two octets, comprising 16 bits, for the network ID. The last two octets are used for host information. The first two octets are used as the network ID, so all Class B hosts that are part of one network will have the same first two octets. The first two bits to the left of Class B addresses must be set to one and zero, and so the first octet has a decimal value of 128 to 191. Class B includes addresses in the range from 128.0.0.0 to 191.255.255.255.

IP

Internet Protocol, or IP, addressing is a logical addressing system that assigns unique identifiers, known as IP addresses, to hosts in a network. Computers use IP addresses to locate one another so they can communicate.

private

Private IP addresses are blocks of IP addresses assigned for use on private networks. Since the addresses are only used on private networks they don't need to be globally unique - just unique on the network on which they are being used.