IPv4 Adressing Flashcards
Automatic Private IP Addressing (APIPA)
A feature that allows clients to self-configure an IPv4 address and subnet mask when a DHCP server is not available. These addresses are not routable on a local network, and typically indicate a problem with host communication.
Binary
A binary number is expressed in a base-2 numerical system, represented by zero (0) values and one (1) values.
Block Size
The increment that we count by in the interesting octet to determine usable IPv4 address ranges. The formula is Block Size = 256 - Interesting Octet Value
Class A Address
In classful network addressing, a Class A address has a value in the first octet ranging from 1 - 126, with a default subnet mask value of 255.0.0.0 (or /8 in prefix notation).
Class B Address
In classful network addressing, a Class B address has a value in the first octet ranging from 128 - 191, with a default subnet mask value of 255.255.0.0 (or /16 in prefix notation).
Class C Address
In classful network addressing, a Class C address has a value in the first octet ranging from 192 - 223, with a default subnet mask value of 255.255.255.0 (or /24 in prefix notation).
Class D Address
Used for multicast purposes, with a value in the first octet ranging from 224 - 239. Because these addresses are never assigned to specific hosts, this address class does not use a subnet mask.
Class E Address
Reserved for research purposes and potential future deployment, these addresses have a value in the first octet ranging from 240 - 255.
Classless Interdomain Routing (CIDR)
Creating a network address by subtracting bits from the natural subnet mask value. Also referred to as prefix notation or slash notation.
DHCP Relay
A host used to forward requests and replies between DHCP clients and servers when they do not reside on the same subnet.
Directed Broadcast Address
The last address in a subnet, used for communicating with all of the IP addresses within the subnet.
Domain Name System (DNS)
Translates human-readable domain names such as kwtrain.com into a computer-readable IP address.
Dotted Decimal Notation
A format for expressing 32-bit IPv4 addresses using four octets separated by decimals.
Dynamic Host Configuration Protocol (DHCP)
A protocol used to automatically provide clients within a network an IP address, subnet mask, default gateway, and DNS server information.
Host Bits
The portion of an IPv4 address represented by a series of contiguous binary 0 values in a 32-bit subnet mask.
Interesting Octet
The last octet in the subnet mask to contain a binary 1 value.
IPv4 Broadcast
IPv4 Broadcast
A one-to-all type of IPv4 communication where one source IP address sends information to every other destination IP address on the local subnet.
IPv4 Multicast
A one-to-many type of IPv4 communication where one source IP addresses sends information to one or more destination IP addresses which are specifically listening for the messages. Traffic is sent to a Class D multicast group address, to which clients can join and receive data.
IPv4 Unicast
A one-to-one type of IPv4 communication where one source IP address sends information to one destination IP address.
Loopback Address
An address used to test the communication and transportation medium locally. Data packets sent to a loopback address are re-routed back to the original node without any alteration. In IPv4, the address 127.0.0.1 is designated as the loopback address.
Network Address
The first address in a subnet, used for identifying the network segment.
Network Bits
The portion of an IPv4 address represented by a series of contiguous binary 1 values in a 32-bit subnet mask.
Octet
A grouping of 8 binary values (or bits) in an IPv4 address, separated by a decimal. Each IPv4 address contains 4 different octets, for a total of 32 bits.
Prefix Notation
A method for notating a subnet mask value in which the number represents how many contiguous binary 1 values are in a 32-bit subnet mask. For example, /8 means there are 8 contiguous binary 1 values, leaving 24 contiguous binary 0 values to complete the 32-bit number. This is also referred to as slash notation.
Private Class A Address
IPv4 addresses that fall within the range of 10.0.0.0 - 10.255.255.255, with a default subnet mask value of 255.0.0.0 (or /8 in prefix notation).
Private Class B Address
IPv4 addresses that fall within the range of 172.16.0.0 - 172.31.255.255, with a default subnet mask value of 255.255.0.0 (or /16 in prefix notation).
Private Class C Address
IPv4 addresses that fall within the range of 192.168.0.0 - 192.168.255.255, with a default subnet mask value of 255.255.255.0 (or /24 in prefix notation).
Private IPv4 Address
An address reserved for internal use on a local network, which is not routable over the public Internet.
Public IPv4 Address
A globally unique address that can be assigned to a device and accessed over the public Internet.
Subnet Mask
A 32-bit number consisting of a series of contiguous binary 1 values followed by a series of contiguous binary 0 values. This is used to delineate the network and host portions of an IPv4 address.
DNS Record Type for IPv4
Address Mapping record (A Record)—also known as a DNS host record, stores a hostname and its corresponding IPv4 address.
Automatic Private IP Addressing (APIPA) Address Ranges
APIPA addresses fall within the range of 169.254.0.0 - 169.254.255.255, with a default subnet mask value of 255.255.0.0 (or /16 in prefix notation).
