---
name: vpc-faq-par
title: FAQ for public address ranges
description: The following questions are commonly asked about public address ranges. If you have additional questions you'd like to see addressed here, open an issue by using the **Open doc issue** or **Edit topic** links at the end of this page.
last-updated: 2026-09-29
---

> ## Documentation Index
> The table of contents for this documentation set is at https://cloud.ibm.com/docs/vpc?format=markdown
> The index for all IBM Cloud docs is at: https://cloud.ibm.com/docs/llms.txt
> Use these files to discover more information as needed.

# FAQ for public address ranges
{: #faq-public-address-ranges}

The following questions are commonly asked about public address ranges. If you have additional questions you'd like to see addressed here, open an issue by using the **Open doc issue** or **Edit topic** links at the end of this page.
{: shortdesc}


## Can I bring my own public IP address range?
{: #assign-public-ips}
{: faq}
{: support}

[BYOIP (IPv4) Beta]{: tag-cyan}
Yes. You can bring your own publicly routable IPv4 address range to IBM Cloud VPC through custom authorized CIDRs. To get started, see [Creating a custom authorized CIDR (BYOIP)](https://cloud.ibm.com/docs/vpc?topic=vpc-provision-custom-authorized-cidr&format=markdown) and open a support case. IBM verifies ownership and configures the range as an authorized CIDR in your account. After the range is available, you can allocate public address ranges and floating IPs from it.


No. Only IBM-provided public IPs are supported. BYOIP (Bring Your Own IP) is not available for this service.

## What public IP address range sizes can I reserve?
{: #prefix-sizes}
{: faq}
{: support}

You can reserve ranges with the following prefix sizes:

* `/28` = 16 IPs
* `/29` = 8 IPs
* `/30` = 4 IPs
* `/31` = 2 IPs
* `/32` = 1 IP

After reserving a range, you can't change its size. Make sure to reserve a range that's large enough to meet your current and future needs.

If you require a prefix size larger than `/28`, review [Public address range quotas](https://cloud.ibm.com/docs/vpc?topic=vpc-quotas&format=markdown#par-quotas) and [contact support](https://cloud.ibm.com/unifiedsupport/cases/form){: external} to request a quota increase.

IPs in different public address ranges aren't guaranteed to be contiguous.
{: note}



## Can I divide a public address range across multiple VPCs or zones?
{: #divide-par}
{: faq}
{: support}

No. A public address range is indivisible. It cannot be split or shared across multiple VPCs or availability zones.

## Can I reserve and use multiple public address ranges in a single VPC?
{: #reserve-use-multiple-public-address-ranges}
{: faq}
{: support}

Yes. You can reserve and bind multiple public address ranges to a single VPC to meet scaling or isolation requirements.

## Are public address ranges automatically redundant across zones?
{: #redundant-by-default}
{: faq}
{: support}

Not by default. However, you can create separate public address ranges in different zones and configure routing to ensure high availability across zones.



## Related links
{: #faq-related-links-par}

- [Getting started with public address ranges](https://cloud.ibm.com/docs/vpc?topic=vpc-about-par&format=markdown)
- [Planning considerations for public address ranges](https://cloud.ibm.com/docs/vpc?topic=vpc-par-planning&format=markdown)
- 
- [IAM roles and actions](https://cloud.ibm.com/docs/iam?topic=iam-iam-service-roles-actions&format=markdown#is.public-address-range-roles)
- [Quotas](https://cloud.ibm.com/docs/vpc?topic=vpc-quotas&format=markdown#par-quotas) and [service limits](https://cloud.ibm.com/docs/vpc?topic=vpc-quotas&format=markdown#service-limits-for-vpc-services)
- [Known issues](https://cloud.ibm.com/docs/vpc?topic=vpc-par-known-issues&format=markdown)
- [Troubleshooting](https://cloud.ibm.com/docs/vpc?group=tbs-par&format=markdown)