Editing IP Addressing

[[Category:Networking]]
== IP Addressing ==
When it comes to your homelab, IP addressing is important. There are a few points to consider before settling on an IP addressing scheme. Keep in mind that changing IPs or mixing and matching IP schemes is not recommended and can be difficult.

=== Picking a Supernet ===
First things first, you want to pick a supernet. Typically, this will be one of the three RFC 1918 private address ranges. I suggest using 10.0.0.0/8 because this gives you well over 16 million IPs to play with - which comes in very handy when implementing VLANs and avoiding overlaps.

{| class="wikitable"
! RFC1918 name !! IP address range !! Number of addresses
! Largest [[Classless Inter-Domain Routing|CIDR]] block (subnet mask) || Host ID size || Mask bits
! ''[[classful network|Classful]]'' description{{refn|group="Note"|[[Classful addressing]] is obsolete and has not been used in the Internet since the implementation of [[Classless Inter-Domain Routing]] (CIDR), starting in 1993.  For example, while {{IPaddr|10.0.0.0|8}} was a single class A network, it is common for organizations to divide it into smaller {{IPaddr||16}} or {{IPaddr||24}} networks. Contrary to a common misconception, a {{IPaddr||16}} subnet of a class A network is not referred to as a class B network. Likewise, a {{IPaddr||24}} subnet of a class A or B network is not referred to as a class C network.  The class is determined by the first three bits of the prefix.<ref>{{cite book|last=Forouzan|first=Behrouz|title=Data Communications and Networking|year=2013|publisher=McGraw Hill|location= New York|isbn= 978-0-07-337622-6|pages= 530–31}}</ref>}}
|-
| 24-bit block || 10.0.0.0 – 10.255.255.255 ||{{gaps|16|777|216}} || 10.0.0.0/8 (255.0.0.0) || 24 bits || 8 bits || single class A network
|-
| 20-bit block || 172.16.0.0 – 172.31.255.255 || {{gaps|1|048|576}} || 172.16.0.0/12 (255.240.0.0) || 20 bits || 12 bits || 16 contiguous class B networks
|-
| 16-bit block || 192.168.0.0 – 192.168.255.255 || {{gaps|65|536}} || 192.168.0.0/16 (255.255.0.0) || 16 bits || 16 bits || 256 contiguous class C networks
|}

==== Avoiding 192.168.0.0/16 ====
I strongly recommend avoiding the 192.168.0.0/16 range of IPs due to backward compatibility issues. The reason is that some older networking devices or software may not recognize classless networking. While you ''can'' do 192.168.0.0/25, this may not make some legacy devices happy. Usually, with classful, you can go smaller, not larger. Although this is rare, you can occasionally run into problems.