IPv4 Range Subtraction
Subtract one arbitrary inclusive IPv4 range from another, returning zero to two exact remaining ranges without subnet or host exclusions.
Description
Subtract one arbitrary inclusive IPv4 range from another, returning zero to two exact remaining ranges without subnet or host exclusions.
Subtracting one inclusive IPv4 range from another can leave zero, one or two ranges.
When to use this tool
Subtract one arbitrary inclusive IPv4 range from another, returning zero to two exact remaining ranges without subnet or host exclusions.
- Prepare the supplied leftStart, leftEnd, rightStart, rightEnd fields for this operation.
- Compare the complete example with the representation used by your own input before carrying the result into another step.
How to use the tool and how it works
- Enter leftStart, leftEnd, rightStart, rightEnd. Use the exact text syntax, units and index conventions explained below.
- Run the tool. If input validation fails, correct the supplied fields before interpreting any result.
- Read result.ranges. Interpret false, null and empty lists using the distinctions below; they can be valid outputs.
Validate both ordered ranges. Preserve the left range when disjoint; otherwise emit portions before the right start and after its end, retaining only portions inside the left range.1
| Input field | Meaning and representation | Accepted input |
|---|---|---|
| leftStart | Address text for the family named by this tool. Prefix lengths are separate fields where shown. | Text; at most 8,192 UTF-16 code units, subject to the grammar above |
| leftEnd | Address text for the family named by this tool. Prefix lengths are separate fields where shown. | Text; at most 8,192 UTF-16 code units, subject to the grammar above |
| rightStart | Address text for the family named by this tool. Prefix lengths are separate fields where shown. | Text; at most 8,192 UTF-16 code units, subject to the grammar above |
| rightEnd | Address text for the family named by this tool. Prefix lengths are separate fields where shown. | Text; at most 8,192 UTF-16 code units, subject to the grammar above |
| Output field | Interpretation |
|---|---|
| result | Object containing the named outputs below. |
| result.ranges | The ranges list in the ordering and representation described above. |
{
"input": {
"leftStart": "10.0.0.1",
"leftEnd": "10.0.0.8",
"rightStart": "10.0.0.4",
"rightEnd": "10.0.0.5"
},
"output": {
"result": {
"ranges": [
{
"start": "10.0.0.1",
"end": "10.0.0.3"
},
{
"start": "10.0.0.6",
"end": "10.0.0.8"
}
]
}
}
}Limitations and assumptions
- Ranges include their endpoints. No CIDR conversion, host filtering or routing context is applied.
- IPv4 input uses strict dotted-decimal octets without leading zeros or surrounding whitespace. IPv6 accepts its supported compressed or full spellings and trims surrounding whitespace, but rejects zone identifiers; embedded dotted IPv4 uses the strict IPv4 spelling. IPv6 address outputs are fully expanded unless stated otherwise.
- All declared input fields are required and unexpected top-level fields are rejected. Numbers must be finite; lists are limited to 128 entries and ordinary text fields to 8,192 UTF-16 code units, with tighter limits where stated.
- JSON text inputs must parse within bounded nesting and size limits. Numeric outputs outside the safe finite range are rejected; large exact integer results use decimal strings. Indexes and half-open spans are zero-based unless a rank is explicitly described as one-based.
Alternative or Complementary methods
Use address-set arithmetic for prefix planning and a routing or interface inspection for deployed configuration. Membership and overlap do not establish reachability, ownership or route preference.
References
Similar or alternative tools
- IPv4 Range Address Count
Count every address in an arbitrary inclusive IPv4 range, not a prefix’s usable-host count; entire 32-bit space remains exact.
- IPv4 Range CIDR Cover
Cover an arbitrary inclusive IPv4 range by a minimal disjoint aligned CIDR sequence; no network/broadcast address subtraction.