> For the complete documentation index, see [llms.txt](https://docs.console.zenlayer.com/welcome/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.console.zenlayer.com/welcome/ip-transit/manage-ip-transit/change-cidr-block.md).

# Change CIDR Block

## Prerequisites

* The instance is **Running**.

## Procedures

1. Click the IP Transit name and go to **Information** > **CIDR block** > **Add CIDR Block**.

   <figure><img src="https://3201622183-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F9X3FDdkCL2HzhbPpPMFt%2Fuploads%2Fgit-blob-f24568071f1c93e65a4ed0c7a8fe4d09036c95b1%2Fimage.png?alt=media" alt=""><figcaption></figcaption></figure>
2. Select the IP type and block size, review the price, and confirm.

   <div align="left"><figure><img src="https://3201622183-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F9X3FDdkCL2HzhbPpPMFt%2Fuploads%2Fgit-blob-a42101f63a72edacf047506c1263ef544cea1f99%2Fimage.png?alt=media" alt="" width="302"><figcaption></figcaption></figure></div>

## Result

The new CIDR block appears in the list.

{% hint style="info" %} <mark style="color:blue;">**Note**</mark>

* <mark style="color:blue;">In Static Routing Mode and Gateway Mode, at least one public CIDR block must remain, so you can only delete a CIDR block if at least two are configured. In BGP Routing Mode, you can delete all CIDR blocks.</mark>
* <mark style="color:blue;">You cannot perform operations while IP Transit is Processing.</mark>
  {% endhint %}