Bulk allocation limits for allocated IP addresses
When you trigger bulk creation of allocated IP records from an IP Subnetwork, the system applies size limits and reserved-address rules before generating the records. This topic describes those limits and the messages displayed when they apply.
Maximum allocation size
A single bulk allocation operation creates at most 64 allocated IP records. The minimum prefix length supported for bulk allocation is therefore /26 for IPv4 and /122 for IPv6 — both equate to 64 addresses.
Attempting bulk allocation on a subnetwork with a shorter (less specific) prefix is rejected with the following error:
Subnetwork {CIDR} contains {N} addresses, which exceeds the maximum of 64 ({/26 or /122}) permitted for bulk IP Address generation. Please subdivide into smaller subnetworks before generating allocated IPs.The {/26 or /122} placeholder is replaced with /26 for IPv4 subnetworks and /122 for IPv6 subnetworks.
Reserved addresses generated during allocation
Bulk allocation creates one record per address in the subnetwork’s CIDR. Addresses that are structurally unassignable are flagged automatically with Is Reserved = True on the resulting allocated IP records. The rule depends on the protocol and prefix.
IPv4 subnetworks:
| Prefix range | Addresses reserved | Notes |
|---|---|---|
| /26 – /30 | First address (network) and last address (broadcast) | Standard IPv4 convention |
| /31 | None | Both addresses usable (RFC 3021 — point-to-point links) |
| /32 | None | Single-host network |
IPv6 subnetworks:
| Prefix range | Addresses reserved | Notes |
|---|---|---|
| /122 – /127 | First address only (Subnet Router Any cast) | RFC 4291. IPv6 has no broadcast address. |
| /128 | None | Single-address network |