> ## Documentation Index
> Fetch the complete documentation index at: https://www.cashfree.com/docs/llms.txt
> Use this file to discover all available pages before exploring further.
# IP Whitelisting
> Whitelist your public IPv4 address for Cashfree Secure ID so only authorised servers can call the Verification APIs in sandbox and production.
Whitelisting your IP address provides a layer of authentication. This prevents unauthorised API requests and ensures only verified requests are processed.
IP whitelisting is required for both the sandbox (test) and production environments. You configure it as a two-factor authentication (2FA) method in the [Merchant Dashboard](https://merchant.cashfree.com/auth/login).
## Prerequisites
Before you whitelist an IP address, ensure the following:
* You have generated Secure ID API credentials. Secure ID client IDs typically start with `CF`. Use Secure ID credentials, not Payment Gateway keys.
* You have a public IPv4 address. Cashfree does not support IPv6, CIDR ranges such as `/24`, or private IP addresses, including the `10.x.x.x`, `172.16.x.x` to `172.31.x.x`, and `192.168.x.x` ranges. Whitelist only individual IPv4 addresses.
* You plan to whitelist no more than 25 IP addresses.
* If your service uses dynamic or range-based outbound IP addresses, for example Render, IP whitelisting may not be feasible. Use the [Signature Generation (Public Key) method](/docs/api-reference/vrs/getting-started#2fa-api-signature-generation) instead.
Complete these steps to generate Secure ID API credentials:
1. Log in to the [Merchant Dashboard](https://merchant.cashfree.com/auth/login).
2. Select the apps icon (nine dots), then select **Secure ID**.
3. Select **Switch to Test** for sandbox credentials, or stay in production for live credentials.
4. Go to **Developers > Two-Factor Authentication** and create the API key.
## Whitelist an IP address
To whitelist your IP address, follow these steps:
1. Log in to the [Merchant Dashboard](https://merchant.cashfree.com/auth/login).
2. Go to **Developers > Two-Factor Authentication** under the **Secure ID** card.
3. Select **IP Whitelist** from the **Select 2FA Method** drop-down.
4. Select **Add IP Address**.
5. Enter the IP address you want to whitelist and select **Add IP Address** to save.
The whitelisted IP addresses are displayed in the grid. After adding a new IP address, wait at least 5 seconds for the change to sync before retrying your API request.
## Switch between 2FA methods
Complete these steps to change the active two-factor authentication method:
1. Log in to the [Merchant Dashboard](https://merchant.cashfree.com/auth/login).
2. Go to **Developers > Two-Factor Authentication**.
3. Select **Switch Method** to toggle between IP Whitelisting and Public Key.
The **Select 2FA Method** drop-down only adds IP addresses or generates keys for the method that is already active. Selecting a different option in that drop-down does not change the active method.
Include the `x-cf-signature` header only when Public Key is the active method. Do not send `x-cf-signature` when IP Whitelisting is the active method.
## Find your IP address
Use your public IPv4 address, not a private or local network address. You can find your public IP address using either of the following methods.
### Use a browser
Open a browser and visit a service such as [whatismyipaddress.com](https://whatismyipaddress.com/).
### Use the command line
From the server that will call the API, run the following command:
```bash theme={"dark"}
curl https://api.ipify.org
```
The command returns your public IPv4 address.