IPv4 CIDR Range Summary
Enter one dotted IPv4 address with optional /0–/32 (default /24). Run locally to normalize the CIDR and show network, upper boundary and host count. For blocks of at most 4096 addresses, read and copy the host list.
About this ipv4 cidr range summary
Enter one dotted IPv4 address with optional /0–/32 (default /24). Run locally to normalize the CIDR and show network, upper boundary and host count. For blocks of at most 4096 addresses, read and copy the host list Performs protocol inspection, IP calculation, and network analysis client-side without sending probes or exposing network topology.
Protocol mechanics & network logic
Performs bitwise subnet calculations and route aggregation in compliance with RFC 4632 (Classless Inter-domain Routing - CIDR), RFC 4291 (IPv6 Addressing Architecture), and RFC 1918 (Private Address Allocations). Deconstructs 32-bit IPv4 integers and 128-bit IPv6 BigInt pairs to calculate network addresses ($N = \text{IP} \ \& \ \text{Mask}$), broadcast boundaries ($B = N \mid \sim\text{Mask}$), wildcard inverse masks, and usable host counts ($2^{32 - P} - 2$ for $P \le 30$). Fully supports RFC 3021 /31 point-to-point links and /32 single host routes.
Worked network diagnostic scenario
Scenario: Normalize an IPv4 CIDR and copy the usable host list.
Sample input:
Processing: Normalize to 192.0.2.0/30, exclude network and broadcast for two listed hosts. /31 includes both endpoints; /32 includes one. Blocks above 4096 total addresses keep only the summary.
Illustrative output:
Addressing limits & protocol boundaries
For /0–/30, exclude the network and broadcast endpoints. For /31, include both endpoints for point-to-point use (RFC 3021). For /32, include the single address. Expansion is limited by total block size: /20–/32, at most 4096 addresses (4094 listed hosts for /20). Larger blocks keep their summary. This local list does not test reachability, allocation or scan targets.
Addressing calculations and subnet models in IPv4 CIDR Range Summary follow IETF RFC definitions. Ensure subnet masks and CIDR prefixes match your network topology.
Offline network inspection boundary
Address parsing and CIDR calculations in IPv4 CIDR Range Summary run entirely client-side without probing external IP networks or transmitting routing data.
IETF RFC specifications & IANA registries
IETF Request for Comments (RFC) standards and IANA registry references:
- RFC 791 (Internet Protocol: IPv4)
- RFC 4632 (Classless Inter-domain Routing: CIDR)
- RFC 4291 (IP Version 6 Addressing Architecture)
IPv4 CIDR Range Summary verification · Audit standards
How to use it
- Enter 192.0.2.1/30 in the text area.
- Click Run locally; the tool validates the four octets and integer prefix, then masks the address to 192.0.2.0.
- Read JSON cidr 192.0.2.0/30, network 192.0.2.0, broadcast 192.0.2.3, and hosts 2. One host per line: 192.0.2.1; 192.0.2.2. Copy host list.
Frequently asked questions
What does IPv4 CIDR Range Summary return?+
Operational requirements for "What does IPv4 CIDR Range Summary return?" are verified in local memory during execution of IPv4 CIDR Range Summary.
Can I try an example?+
Enter `192.0.2.1/30` and choose Run locally. It returns `192.0.2.0/30`, network `192.0.2.0`, broadcast `192.0.2.3`, and hosts `2`.
How are /31 and /32 handled?+
The arithmetic host count is 2 for `/31` and 1 for `/32`. For those two prefixes, the field named broadcast is only the upper address of the block, not a protocol broadcast address.
Is the prefix optional?+
Yes: an omitted prefix defaults to `/24`; a supplied prefix must be an integer from 0 through 32. An empty suffix, extra slash, malformed IPv4, or out-of-range prefix is rejected.