NETWORK TOOLKIT / 01
Subnet Calculator.
Exact address ranges, masks, and network boundaries.
Define your network
192.168.10.0/24
192.168.10.0192.168.10.255255.255.255.00.0.0.255192.168.10.255Private NetworkInside the address
32 bits · 4 octetsReverse DNS & Delegation
PTR name for the input address
0.10.168.192.in-addr.arpa.Network delegation
10.168.192.in-addr.arpa.Standard Networking Rules
IPv4 LANs reserve network and broadcast addresses. /31 has 2 point-to-point addresses; /32 is a single host. IPv6 has no broadcast; total addresses are not an assignable-host guarantee.
Provider / Standard Reference ↗Cloud profiles model subnet size and reservations, not full deployment eligibility. IPv6 total address space is not an assignable-host count.
NETWORK TOOLKIT / 02
Subnet Planner.
Allocate subnets, reserve capacity, and plan for growth.
Plan Settings
Opening local plans…DNS Defaults & Plan Files
Separate domains with commas or spaces.
IPv4 or IPv6 addresses. No live lookups.
Subnet Allocations 3
Largest requirements first. Fixed and reserved blocks stay in place.
| Name / VLAN | Requirement | Allocated CIDR | Usable / Type | Actions |
|---|---|---|---|---|
| Staff Network | 100 | Awaiting Allocation | — | |
| Voice | 40 | Awaiting Allocation | — | |
| Guest Wi-Fi | 60 | Awaiting Allocation | — |
Awaiting AllocationRequirement: 100 · Available: —Awaiting AllocationRequirement: 40 · Available: —Awaiting AllocationRequirement: 60 · Available: —Address Space
10.20.0.0/22Plans are saved only in this browser. Download JSON backups before clearing browser data.
NETWORK TOOLKIT / 03
Range Tools.
Split, compare, and consolidate address space.
NETWORK TOOLKIT / 04
Network Reference.
The numbers and conventions worth keeping close.
Prefix Reference
| Prefix | Subnet Mask | Total Addresses | Usable (Standard) |
|---|---|---|---|
| /0 | 0.0.0.0 | 4294967296 | 4294967294 |
| /1 | 128.0.0.0 | 2147483648 | 2147483646 |
| /2 | 192.0.0.0 | 1073741824 | 1073741822 |
| /3 | 224.0.0.0 | 536870912 | 536870910 |
| /4 | 240.0.0.0 | 268435456 | 268435454 |
| /5 | 248.0.0.0 | 134217728 | 134217726 |
| /6 | 252.0.0.0 | 67108864 | 67108862 |
| /7 | 254.0.0.0 | 33554432 | 33554430 |
| /8 | 255.0.0.0 | 16777216 | 16777214 |
| /9 | 255.128.0.0 | 8388608 | 8388606 |
| /10 | 255.192.0.0 | 4194304 | 4194302 |
| /11 | 255.224.0.0 | 2097152 | 2097150 |
| /12 | 255.240.0.0 | 1048576 | 1048574 |
| /13 | 255.248.0.0 | 524288 | 524286 |
| /14 | 255.252.0.0 | 262144 | 262142 |
| /15 | 255.254.0.0 | 131072 | 131070 |
| /16 | 255.255.0.0 | 65536 | 65534 |
| /17 | 255.255.128.0 | 32768 | 32766 |
| /18 | 255.255.192.0 | 16384 | 16382 |
| /19 | 255.255.224.0 | 8192 | 8190 |
| /20 | 255.255.240.0 | 4096 | 4094 |
| /21 | 255.255.248.0 | 2048 | 2046 |
| /22 | 255.255.252.0 | 1024 | 1022 |
| /23 | 255.255.254.0 | 512 | 510 |
| /24 | 255.255.255.0 | 256 | 254 |
| /25 | 255.255.255.128 | 128 | 126 |
| /26 | 255.255.255.192 | 64 | 62 |
| /27 | 255.255.255.224 | 32 | 30 |
| /28 | 255.255.255.240 | 16 | 14 |
| /29 | 255.255.255.248 | 8 | 6 |
| /30 | 255.255.255.252 | 4 | 2 |
| /31 | 255.255.255.254 | 2 | 2 |
| /32 | 255.255.255.255 | 1 | 1 |
Standard Networking
IPv4 LANs reserve network and broadcast addresses. /31 has 2 point-to-point addresses; /32 is a single host. IPv6 has no broadcast; total addresses are not an assignable-host guarantee.
Read the Source ↗Verified 2026-09-10. Capacity and prefix guidance; not full cloud deployment validation.
AWS VPC
IPv4 /16–/28: first 4 and last address reserved. IPv6 /44–/64 in steps of 4: first 4 and last address reserved. BYOIP exceptions and service quotas are outside this profile.
Read the Source ↗Verified 2026-09-10. Capacity and prefix guidance; not full cloud deployment validation.
Azure VNet
IPv4 /2–/29: first 4 and last address reserved. IPv6 subnets must be /64. Service-specific subnet sizes and deployment restrictions still apply.
Read the Source ↗Verified 2026-09-10. Capacity and prefix guidance; not full cloud deployment validation.
Google Cloud · Primary
IPv4 /4–/29: first 2 and last 2 addresses reserved. IPv6 subnets are /64, with /96 interface allocations. Internal IPv6 reserves the first and last /96; external space is split into /65 halves for VMs and forwarding rules. Restricted address ranges still apply.
Read the Source ↗Verified 2026-09-10. Capacity and prefix guidance; not full cloud deployment validation.
Google Cloud · Secondary IPv4
IPv4 secondary ranges use /4–/29, with no reserved addresses and no virtual gateway. Restricted address ranges and service-specific requirements still apply.
Read the Source ↗Verified 2026-09-10. Capacity and prefix guidance; not full cloud deployment validation.
IPv4 /31 & /32
A /31 point-to-point link has 2 usable addresses under RFC 3021. A /32 represents one host. Host-count planning defaults to LAN subnets; request these prefixes explicitly when needed.
RFC 3021 ↗IPv6 Addressing & SLAAC
IPv6 has no broadcast address. A /64 is the normal LAN boundary for SLAAC. The size of a block is not a promise that every address can be assigned: subnet-router anycast and platform rules matter. /127 is used for point-to-point links and /128 for individual addresses.
IPv6 Addressing Architecture ↗Private, Shared & Documentation Space
Private IPv4: 10.0.0.0/8, 172.16.0.0/12, 192.168.0.0/16. Shared CGNAT: 100.64.0.0/10. IPv6 unique-local: fc00::/7; link-local: fe80::/10. Use documentation prefixes for examples. Classification describes address space, not actual reachability or routing.
DNS & Reverse Delegation
IPv4 PTR names reverse the four octets under in-addr.arpa. IPv6 reverses all 32 hexadecimal nibbles under ip6.arpa. Network delegation is simplest on octet boundaries for IPv4 and nibble boundaries for IPv6. DNS names and resolver addresses in plans are metadata; a missing DNS record does not prove an address is unused.