IPv4 & IPv6
Introduction to IPv4 Addressing
An IPv4 address is a 32-bit hierarchical address that is composed of a network portion and a host portion. It is a logical address that is assigned to all computing devices, and it can either be static or dynamic. IPv4 addresses are made up of 4 octets with a maximum value of 255 in each byte.
Classful IP Addresses
| Address Class | Range | Default Subnet Mask |
|---|---|---|
| A | 1.0.0.0 to 126.255.255.255 | 255.0.0.0 |
| B | 128.0.0.0 to 191.255.255.255 | 255.255.0.0 |
| C | 192.0.0.0 to 223.255.255.255 | 255.255.255.0 |
| D | 224.0.0.0 to 239.255.255.255 | Reserved for Multicasting |
| E | 240.0.0.0 to 254.255.255.255 | Experimental |
Note: Class A addresses 127.0.0.0 to 127.255.255.255 cannot be used and are reserved for loopback testing.
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IP Addresses are divided into five classes, and each class has a "default" subnet mask that can be assumed if one is not specified. Class A addresses from 127.0.0.0 to 127.255.255.255 are reserved for loopback testing. For example, addresses such as 172.16.0.0 or 255.255.240.0 fall into Class B, with a default subnet mask of 255.255.0.0.
Private IP Address Ranges
RFC 1918 defines private address ranges that are not reachable from the internet and can be reused within private networks. A computer at your house could have an IP Address of 192.168.0.100 because it is considered a "private" internal address. The private IP address ranges to know are 10.0.0.0 - 10.255.255.255, 172.16.0.0 - 172.31.255.255, and 192.168.0.0 - 192.168.255.255.
Unavailable Network Addresses
Some network addresses are unavailable to be used on the public web, such as loopback address (127.0.0.0 - 127.255.255.255), 10.0.0.0 - 10.255.255.255, 172.16.0.0 - 172.16.31.255, and 192.168.0.0 - 192.168.255.255. Almost 300 million IP addresses are unusable. Private IP addresses are actually a good thing as they enable IP address recycling.
Types of IPv4 Communication Transmissions
There are three types of transmissions that affect the destination IPv4 Addresses. Unicast transmission refers to one device sending information in a one-to-one format, while broadcast transmission refers to a device sending a message to all the devices on a network in one-to-all communication. Multicast transmission allows a host to send a single packet to a selected set of hosts that are in the multicast group, and IPv4 has reserved 224.0.0.0 - 239.255.255.255 addresses as a multicast range. Anycast address is any IPv6 unicast address that can be assigned to multiple devices. IPv4 uses broadcast packets, but IPv6 does not.
APIPA
APIPA Address range is 169.254.0.0 - 169.254.255.255. When first turning on a PC, it will ask for a DHCP server for an IP address on the network, and DHCP will assign an APIPA to a device when there is no DHCP server available. It is represented as 169.254.x.x.
Summary
An IPv4 address is a logical address that is assigned to all computing devices and consists of a network portion and a host portion. It can be static or dynamic and is made up of 4 octets with a maximum value of 255 in each byte.
IP addresses are divided into five classes with a default subnet mask that can be assumed if one is not specified. Class A addresses from 127.0.0.0 to 127.255.255.255 are reserved for loopback testing, while Class B addresses fall into 172.16.0.0 - 172.31.255.255 range, and Class C addresses fall into 192.168.0.0 - 192.168.255.255 range.
Private address ranges are defined in RFC 1918 and include 10.0.0.0 - 10.255.255.255, 172.16.0.0 - 172.31.255.255, and 192.168.0.0 - 192.168.255.255. These addresses are not reachable from the internet and can be reused within private networks.
Some network addresses are unavailable for use on the public web, such as the loopback address and private IP ranges, making almost 300 million IP addresses unusable. Private IP addresses enable IP address recycling.
There are three types of transmissions that affect destination IPv4 addresses. Unicast transmission sends information in a one-to-one format, broadcast transmission sends a message to all devices on a network in one-to-all communication, and multicast transmission allows a host to send a single packet to a selected set of hosts that are in the multicast group.
The APIPA address range is 169.254.0.0 - 169.254.255.255, and it is assigned to a device when no DHCP server is available. DHCP assigns an IP address to a device when it is turned on and requests one on the network.
Introduction to IPv6
IPv6 was created as a solution to the problem of IP addresses running out in IPv4. It consists of 182 bits for 340 undecillion IP addresses, which are written in a string of hexadecimal characters. Each four bits make one hexadecimal value, resulting in a total of 32 0x values. The IPv6 address is made up of 8 hextets, which equals a 16-bit segment. The maximum value of a 16-bit segment is 65,535, and the total of 32x4 is a 128-bit hexadecimal address. The maximum potential range for IPv6 is 0000 : 0000 : 0000 : 0000 : 0000 : 0000 : 0000 : 0000 to FFFF : FFFF : FFFF : FFFF : FFFF : FFFF : FFFF : FFFF.
Transitioning from IPv4 to IPv6
There are several ways to transition from IPv4 to IPv6. Dual stack devices allow both IPv4 and IPv6 to coexist on the same network segment. Tunneling is a method of transporting an IPv6 packet over an IPv4 network, with the IPv6 packet being encapsulated inside an IPv4 packet. Network Address Translation (NAT64) allows IPv6-enabled devices to communicate with IPv4-enabled devices using a translation technique similar to NAT for IPv4.
The Math of IPv6
IPv6 has a massive potential range of IP addresses, and the 0x value of 'F' is 15, the maximum for four bits. The binary value of 'FF' is 255, the maximum for eight bits.
Organizations Involved in the Development of IPv6
The Internet Engineering Task Force (IETF) developed IPv6 to replace IPv4, while the Internet Assigned Numbers Authority (IANA) owns every IPv6 address and assigns specific ranges to Regional Internet Registries (RIRs). There are five RIRs, including AFRINIC, APNIC, ARIN, LACNIC, and RIPE NCC, with ARIN being where ISPs like Verizon obtain IPv6 address ranges that are handed out to households and businesses in North America.
Abbreviating IP Addresses
There are two rules for abbreviating IPv6 addresses. The first rule is to omit leading zeroes, removing unnecessary zeroes like significant digits in chemistry. The second rule is to double colon, mushing all the blank zeroes into one spot. It can only be used once.
Summary
Dual stack devices allow both IPv4 and IPv6 to coexist on the same network segment.
Tunneling is a method of transporting an IPv6 packet over an IPv4 network.
Network Address Translation (NAT64) allows IPv6-enabled devices to communicate with IPv4-enabled devices using a translation technique similar to NAT for IPv4.
IPv6 has a massive potential range of IP addresses.
The maximum value for four bits is 15, and the maximum value for eight bits is 255.
The Internet Engineering Task Force (IETF) developed IPv6 to replace IPv4.
The Internet Assigned Numbers Authority (IANA) owns every IPv6 address and assigns specific ranges to Regional Internet Registries (RIRs).
There are five RIRs, including AFRINIC, APNIC, ARIN, LACNIC, and RIPE NCC, with ARIN being where ISPs like Verizon obtain IPv6 address ranges that are handed out to households and businesses in North America.
Two rules for abbreviating IPv6 addresses:
Omit leading zeroes and double colon to mush all the blank zeroes into one spot.
The double colon can only be used once.