Legacy IPv4 /8 Allocations (The Early Internet)
Overview
In the early days of the Internet, massive IPv4 address blocks (/8 networks, called “Class A”) were assigned to single institutions, government agencies, or research organizations.
These addresses are still in the global routing table today, but their usage patterns and ownership may have changed over decades.
This CSV explains these historic allocations and why they matter.
What This CSV Contains
Large historical blocks such as:
- 6.0.0.0/8
- 7.0.0.0/8
- 8.0.0.0/8
- 11.0.0.0/8
- 21.0.0.0/8
- 22.0.0.0/8
- 25.0.0.0/8
- 26.0.0.0/8
- 29.0.0.0/8
- 30.0.0.0/8
- 55.0.0.0/8
Each row includes:
- The CIDR block
- A high-level description
- Summary of historical context
- Notes explaining relevance
This page is ideal for:
- People learning why IPv4 exhaustion happened
- Illustrating early-era allocation policies
- Helping engineers read routing tables with context
| CIDR | Name | Summary | Notes |
|---|---|---|---|
| 6.0.0.0/8 | Legacy Large Allocation | Historically assigned as a single /8 to a major organization/government entity. | Appears in discussions about legacy 'Class A' space; operational use may change over time. |
| 7.0.0.0/8 | Legacy Large Allocation | Large historic block, sometimes cited in address conservation discussions. | Representative of early-era large IPv4 allocations. |
| 8.0.0.0/8 | Legacy /8 Example | Large /8 historically held and partially used by a major provider. | Often referenced when discussing early allocations vs modern scarcity. |
| 11.0.0.0/8 | Legacy Large Allocation | Historic /8 allocation to government/large institutional use. | Used in examples of legacy 'Class A' assignments. |
| 21.0.0.0/8 | Legacy Large Allocation | Historic /8 block used in research/government contexts. | Representative of early-era allocations; treat as normal public space operationally. |
| 22.0.0.0/8 | Legacy Large Allocation | Another historic /8, often referenced in policy and research. | Reminder that many /8s are tied to historic one-org assignments. |
| 25.0.0.0/8 | Legacy Large Allocation | Historic /8 associated with government/defense use. | Sometimes appears in network examples and legacy policy documents. |
| 26.0.0.0/8 | Legacy Large Allocation | Historic large block used in government or specialized networks. | Operational status may vary; used here as an example of legacy /8 usage. |
| 29.0.0.0/8 | Legacy Large Allocation | Large historic /8 space. | Part of the 'legacy /8' conversation in IPv4 address policy discussions. |
| 30.0.0.0/8 | Legacy Large Allocation | Another example of a single-entity /8 assignment. | Illustrates how much space a /8 actually represents. |
| 55.0.0.0/8 | Legacy Large Allocation | Historic /8 tied to a single large organization. | Commonly appears in examples of legacy allocations. |