E-mail Protocols
The Post Office Protocol version 3 (POP3); Internet Message Access Protocol (IMAP); Simple Mail Transfer Protocol (SMTP).
Domain Name System (DNS)
Name-to-address resolution protocol that keeps a list of computer names and their IP addresses.
IPv4 addresses
32-bit (4-byte) logical addresses.
octets
32-bit IPv4 addresses are grouped into four 8-bit --
0 to 255
Each IPv4 address octet is represented by a decimal number from -- to --.
dotted decimal notation, as in 172.24.208.192.
The four IPv4 addresses decimal numbers are separated by periods in a format called --.
the address space
The number of host addresses in a network.
256
2^8 yields -- possible addresses.
A, B, C, D, or E.
IP addresses are categorized in ranges referred to as Classes --.
Class A
The value of the first octet for this Class of IP addresses is between 1 and 127. Class -- addresses are intended for use by large corporations and governments. An IP address
registry assigns the first octet, leaving the last three octets for network admi
Class B
This class IP addresses begin with network IDs between 128 and 191 and are intended for use in medium to large networks. An IP address registry assigns the first two octets, leaving the third and fourth octets available for administrators to assign as hos
Class C
This Class of IP addresses are intended for small networks. An IP address registry assigns the first three octets, ranging from 192 to 223. In the Class -- address 211.255.49.254, for example, the network ID is 211.255.49. These networks are limited to 25
Class D
This Class of IP addresses are reserved for multicasting, in which a packet is addressed so that more than one destination can receive it. Applications using this feature include videoconferencing and streaming media. In a Class -- address, the first octe
Class E
This Class of IP addresses have a value from 240 to 255 in the first octet. This range of addresses is reserved for experimental use and can't be used for address assignment.
10 (one Class A network address)
The reserved addresses Class A addresses begin with --.
172.16 to 172.31 (16 Class B network addresses)
The reserved addresses Class B addresses are from -- to --.
192.168.0 to 192.168.255 (256 Class C network addresses)
The reserved addresses Class C addresses are from - to --.
Network Address Translation (NAT)
-- helps more by allowing an organization to use private IP addresses while connected to the Internet.
Port Address Translation (PAT)
An extension of NAT, called -- , allows several hundred workstations to access the Internet with a single public Internet address.
Classless Interdomain Routing (CIDR)
With this scheme, when an address is assigned, the network and host IDs don't always begin and end on octet boundaries according to the IP address class; instead, the network ID and host ID can be almost any number of bits (with the combined number of bit
Subnetting
-- is the process of dividing a single network address into two or more smaller addresses, each with fewer available host IDs than the original network address.
subnet mask
IP uses an address's -- to determine which part of the address denotes the network portion and which part denotes the host. It's a 32-bit number in dotted decimal format consisting of a string of eight or more binary 1s followed by a string of 0s.
1
A binary -- in the subnet mask signifies that the corresponding bit in the IP address belongs to the network address.
0
A binary -- signifies that the corresponding bit in the IP address belongs to the host ID.
255.0.0.0
Default subnet mask for Class A:
255.255.0.0
Default subnet mask for Class B:
255.255.255.0
Default subnet mask for Class C:
subnet mask
All devices on a single logical network (meaning each device can communicate with another device without going through a router� sometimes called a network segment) must share the same network address and, therefore, use the same --.
Supernetting; supernet.
-- reallocates bits from the network portion of an IP address to the host portion, effectively making two or more smaller subnets a larger -- ; allows combining two or more consecutive IP network addresses and make them function as a single logical networ
IPv6
-- will eventually replace IPv4 because of its larger 128-bit address space and builtin security and QoS features.
IPv6 address
-- are expressed as eight four-digit hexadecimal values.
a public topology, a site
topology, and an interface identifier
In the IPv6 address space, an addressing hierarchy of three parts used are:
public topology
The first three 16-bit sections (totaling 48 bits) of an IPv6 address represent the --, which could be an Internet backbone service provider, for example.
site topology
The next 16 bits of an IPv6 address represent the --, such as a business or a local ISP.
interface identifier
The last 64 bits (four 16-bit sections) of an IPv6 address represent the --, which is derived from the MAC address on the host's NIC. The interface identifier is the unique host address.
Hexadecimal, or just
hex,
Based on powers of 16 and uses 16 symbols, the numbers 0-9 and letters A- F.
Class A Private Address
10.0.0.0/8. If an IP address begins with the number 10, it is a class A private address.
Class B Private Address
172.16.0.0/12. If an IP address begins with 172.16-31, it is a class B private address.
Class C Private Address
192.168.0.0/16. If an IP address begins with 192.168, it is a class C private address.