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There are five classes: A, B, C, D and E in the IPv4 IP address space. Primarily, class A, B, and C are used by the majority of devices on the Internet. Class D and class E are for special uses. Each class has a specific range of IP addresses.<ref>https://www.meridianoutpost.com/resources/articles/IP-classes.php</ref> | There are five classes: A, B, C, D and E in the IPv4 IP address space. Primarily, class A, B, and C are used by the majority of devices on the Internet. Class D and class E are for special uses. Each class has a specific range of IP addresses.<ref>https://www.meridianoutpost.com/resources/articles/IP-classes.php</ref> | ||
Within each network class, there are designated IP address that is reserved specifically for private/internal use only. Private IP address cannot be used on Internet-facing devices as they are non-routable - not allowed to be routed outside of your network. | Within each network class, there are designated IP address that is reserved specifically for private/internal use only. Private IP address cannot be used on Internet-facing devices as they are non-routable - not allowed to be routed outside of your internal network. | ||
{| class="wikitable" | {| class="wikitable" | ||
|+ | |+ | ||
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| | | | ||
|Research/Reserved/Experimental | |Research/Reserved/Experimental | ||
|} | |||
== Network prefix vs Host ID == | |||
Network prefix describes the specific location on the network to find where that IP addresses are located on. Network prefix portion is being used by Router to send packets through an internetwork becuase Routers are not concerned about host addresses. | |||
=== Two type of routing === | |||
* Classless routing : the practice of assigning different size masks on your network—does not work unless you run a routing protocol that supports prefix routing. RIP version 2, OSPF, and EIGRP are examples of routing protocols that can [[support]] classless routing. | |||
* Classful routing : means that all hosts have the same size mask. RIP version 1 and IGRP are classful routing protocols, and neither will work in a classless environment. | |||
If you wanted to create smaller networks (sub networks) out of a Class A network ID, you’d borrow bits from the host portion of the mask. The more bits you borrow, the more subnets you can have, but this means fewer hosts per subnet. '''following''' lists all the available Class A subnet masks:<ref>https://www.techrepublic.com/article/subnet-a-class-a-network-with-ease/</ref> | |||
'''Subnetting divides a network into smaller subnets.''' Subnetting applies equally whether you working with either private or public addresses. It becomes even more important when you’re working with '''globally routed IP space.'''<ref>https://en.wikipedia.org/wiki/Subnetwork#Determining_the_network_prefix</ref> | |||
Once we define a mask for subclassing large network to small network by assign subnet mask and validate subnet address, to valid subnet address ipcalc would be simplest way to | |||
{| class="wikitable" | |||
|+Available Class A subnet masks | |||
|Mask | |||
|Prefix | |||
|Subnets | |||
|Hosts | |||
|- | |||
|255.0.0.0 | |||
|(/8) | |||
|1 network | |||
|with 16,777,214 hosts | |||
|- | |||
|255.128.0.0 | |||
|(/9) | |||
|2 subnets | |||
|with 8,388,606 hosts each | |||
|- | |||
|255.192.0.0 | |||
|(/10) | |||
|4 subnets | |||
|with 4,194,302 hosts each | |||
|- | |||
|255.224.0.0 | |||
|(/11) | |||
|8 subnets | |||
|with 2,097,150 hosts each | |||
|- | |||
|255.240.0.0 | |||
|(/12) | |||
|16 subnets | |||
|with 1,048,574 hosts each | |||
|- | |||
|255.248.0.0 | |||
|(/13) | |||
|32 subnets | |||
|with 524,286 hosts each | |||
|- | |||
|255.252.0.0 | |||
|(/14) | |||
|64 subnets | |||
|with 262,142 hosts each | |||
|- | |||
|255.254.0.0 | |||
|(/15) | |||
|128 subnets | |||
|with 131,070 hosts each | |||
|- | |||
|255.255.0.0 | |||
|(/16) | |||
|256 subnets | |||
|with 65,534 hosts each | |||
|- | |||
|255.255.128.0 | |||
|(/17) | |||
|512 subnets | |||
|with 32,766 hosts each | |||
|- | |||
|255.255.192.0 | |||
|(/18) | |||
|1,024 subnets | |||
|with 16,384 hosts each | |||
|- | |||
|255.255.224.0 | |||
|(/19) | |||
|2,048 subnets | |||
|with 8,190 hosts each | |||
|- | |||
|255.255.240.0 | |||
|(/20) | |||
|4,096 subnets | |||
|with 4,094 hosts each | |||
|- | |||
|255.255.248.0 | |||
|(/21) | |||
|8,192 subnets | |||
|with 2,046 hosts each | |||
|- | |||
|255.255.252.0 | |||
|(/22) | |||
|16,384 subnets | |||
|with 1,022 hosts each | |||
|- | |||
|255.255.254.0 | |||
|(/23) | |||
|32,768 subnets | |||
|with 510 hosts each | |||
|- | |||
|255.255.255.0 | |||
|(/24) | |||
|65,536 subnets | |||
|with 254 hosts each | |||
|- | |||
|255.255.255.128 | |||
|(/25) | |||
|131,072 subnets | |||
|with 126 hosts each | |||
|- | |||
|255.255.255.192 | |||
|(/26) | |||
|262,144 subnets | |||
|with 62 hosts each | |||
|- | |||
|255.255.255.224 | |||
|(/27) | |||
|524,288 subnets | |||
|with 30 hosts each | |||
|- | |||
|255.255.255.240 | |||
|(/28) | |||
|1,048,576 subnets | |||
|with 14 hosts each | |||
|- | |||
|255.255.255.248 | |||
|(/29) | |||
|2,097,152 subnets | |||
|with 6 hosts each | |||
|- | |||
|255.255.255.252 | |||
|(/30) | |||
|4,194,304 subnets | |||
|with 2 hosts each | |||
|} | |} | ||
== References == | == References == | ||
<references /> | <references /> | ||
Revision as of 19:51, 5 July 2023
The Five IPv4 Classes
There are five classes: A, B, C, D and E in the IPv4 IP address space. Primarily, class A, B, and C are used by the majority of devices on the Internet. Class D and class E are for special uses. Each class has a specific range of IP addresses.[1]
Within each network class, there are designated IP address that is reserved specifically for private/internal use only. Private IP address cannot be used on Internet-facing devices as they are non-routable - not allowed to be routed outside of your internal network.
| Class | Public IP Range | Private IP Range | Special IP Range | Subnet Mask | Number of Networks | Number of Hosts per Network |
|---|---|---|---|---|---|---|
| A | 1.0.0.0 to 127.0.0.0 | 10.0.0.0 to 10.255.255.255
CIDR[2] example (10.0.0.0/8) |
255.0.0.0 | 126 | 16,777,214 | |
| B | 128.0.0.0 to 191.255.0.0 | 172.16.0.0 to 172.31.255.255
CIDR example, (172.16.0.0/16) |
Automatic Private IP Addressing (APIPA) is a feature with Microsoft Windows-based computers to automatically assign itself an IP address within this range if a Dynamic Host Configuration Protocol (DHCP) server is not available on the network. | 255.255.0.0 | 16,382 | 65,534 |
| C | 192.0.0.0 to 223.255.255.0 | 192.168.0.0 to 192.168.255.255
CIDR example, (192.168.0.0/24) |
127.0.0.1 to 127.255.255.255
**network testing addresses (also referred to as loop-back addresses). |
255.255.255.0 | 2,097,150 | 254 |
| D | 224.0.0.0 to 239.255.255.255 | Multicasting | ||||
| E | 240.0.0.0 to 255.255.255.255 | Research/Reserved/Experimental |
Network prefix vs Host ID
Network prefix describes the specific location on the network to find where that IP addresses are located on. Network prefix portion is being used by Router to send packets through an internetwork becuase Routers are not concerned about host addresses.
Two type of routing
- Classless routing : the practice of assigning different size masks on your network—does not work unless you run a routing protocol that supports prefix routing. RIP version 2, OSPF, and EIGRP are examples of routing protocols that can support classless routing.
- Classful routing : means that all hosts have the same size mask. RIP version 1 and IGRP are classful routing protocols, and neither will work in a classless environment.
If you wanted to create smaller networks (sub networks) out of a Class A network ID, you’d borrow bits from the host portion of the mask. The more bits you borrow, the more subnets you can have, but this means fewer hosts per subnet. following lists all the available Class A subnet masks:[3]
Subnetting divides a network into smaller subnets. Subnetting applies equally whether you working with either private or public addresses. It becomes even more important when you’re working with globally routed IP space.[4]
Once we define a mask for subclassing large network to small network by assign subnet mask and validate subnet address, to valid subnet address ipcalc would be simplest way to
| Mask | Prefix | Subnets | Hosts |
| 255.0.0.0 | (/8) | 1 network | with 16,777,214 hosts |
| 255.128.0.0 | (/9) | 2 subnets | with 8,388,606 hosts each |
| 255.192.0.0 | (/10) | 4 subnets | with 4,194,302 hosts each |
| 255.224.0.0 | (/11) | 8 subnets | with 2,097,150 hosts each |
| 255.240.0.0 | (/12) | 16 subnets | with 1,048,574 hosts each |
| 255.248.0.0 | (/13) | 32 subnets | with 524,286 hosts each |
| 255.252.0.0 | (/14) | 64 subnets | with 262,142 hosts each |
| 255.254.0.0 | (/15) | 128 subnets | with 131,070 hosts each |
| 255.255.0.0 | (/16) | 256 subnets | with 65,534 hosts each |
| 255.255.128.0 | (/17) | 512 subnets | with 32,766 hosts each |
| 255.255.192.0 | (/18) | 1,024 subnets | with 16,384 hosts each |
| 255.255.224.0 | (/19) | 2,048 subnets | with 8,190 hosts each |
| 255.255.240.0 | (/20) | 4,096 subnets | with 4,094 hosts each |
| 255.255.248.0 | (/21) | 8,192 subnets | with 2,046 hosts each |
| 255.255.252.0 | (/22) | 16,384 subnets | with 1,022 hosts each |
| 255.255.254.0 | (/23) | 32,768 subnets | with 510 hosts each |
| 255.255.255.0 | (/24) | 65,536 subnets | with 254 hosts each |
| 255.255.255.128 | (/25) | 131,072 subnets | with 126 hosts each |
| 255.255.255.192 | (/26) | 262,144 subnets | with 62 hosts each |
| 255.255.255.224 | (/27) | 524,288 subnets | with 30 hosts each |
| 255.255.255.240 | (/28) | 1,048,576 subnets | with 14 hosts each |
| 255.255.255.248 | (/29) | 2,097,152 subnets | with 6 hosts each |
| 255.255.255.252 | (/30) | 4,194,304 subnets | with 2 hosts each |