Separate documentation from private deployment
04A diagram on paper and a running local network are different uses. RFC 5737 explicitly says its blocks are not for local use.
RFC 1918 private IPv4 space is a different resource, such as 10.0.0.0/8. It requires a suitable local plan and is not globally unique. This is not automatic renumbering.
Source for this drawing: RFC 5737 · Read RFC section 4 ↗
New to this? Start hereA quick picture + helpful background
A message needs an address.
Think of a packet as a small addressed envelope. Devices pass it onward; transport protocols decide what delivery promises an application gets.
Helpful first, if these ideas are unfamiliar
These pictures are analogies to help you learn. The linked RFC explains the actual rules.
Terms in this drawing
Related RFCs and changes
“Updates” changes part of an earlier RFC. “Obsoletes” replaces it. This list shows selected related documents.
A documentation reservation does not grant a local deployment range.
- TEST-NET blocks are not for local use; filters may apply in both local and public contexts.
- RFC 1918 defines separate private IPv4 space. Its addresses are not globally unique.
- Choose an appropriate deployment addressing plan; changing a caption does not make an address suitable for a live network.
Examples are documentation text, not a network configuration. No packets are sent. SHOULD and SHOULD NOT are recommendations, not MUST. Valid exceptions require understanding and carefully weighing the full implications (RFC 2119 §§3–4). Private-address background: RFC 1918 §§3–4 (linked as a companion), not a new RFC 5737 allocation.
Read the RFC section ↗