# Add or Ignore subdomains in Attack Surface

By default, Aikido automatically discovers subdomains related to your domain. In some cases, you may want to manually add a subdomain (for assets that aren’t detected automatically) or exclude a subdomain (for assets that fall outside of your scope or don’t need scanning).

## Why manage subdomains?

* Add subdomains: Ensure important assets (like api.example.com) are included in your security scans.
* Exclude subdomains: Reduce noise and avoid scanning third-party or out-of-scope services (like a test environment or marketing site hosted elsewhere).

## Adding a subdomain

1. Navigate to your domain overview page.
2. Go to the Subdomains tab.
3.  Click Add Subdomain in the top right.<br>

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4.  Enter the subdomain you want to monitor.<br>

    <figure><img src="https://help.aikidogov.us/_assets/02e895f34a27/Screenshot-2025-09-19-at-11.00.36.png" alt=""><figcaption></figcaption></figure>
5. Confirm to include it in future scans.

## Excluding a subdomain

1. From the Subdomains tab, find the subdomain in the list.
2.  Open the Actions menu (three dots on the right).<br>

    <figure><img src="https://help.aikidogov.us/_assets/01897320e07f/Screenshot-2025-09-19-at-11.00.30.png" alt=""><figcaption></figcaption></figure>
3. Select Exclude Subdomain.
4. The subdomain will no longer be scanned.