# Restrict user email addresses to certain domains

We allow administrators to block new users from signing up who are not in
 the organization. The administrator can accomplish this by restricting
 users to have email addresses only from the organization's domains.

{!go-to-the.md!} [Organization settings](/#administration/)
{!admin.md!}

2. Restricting user email addresses to certain domains can be enabled or disabled
 with the **Users restricted to (allowed domains)** checkbox shown below:

    ![Restrict domains checkbox](/static/images/help/restrict-domains-checkbox.png)

    !!! tip ""
        The allowed domains will be listed after the **Users restricted to**
         next to the checkbox.

3. Domains can be added to the allowed domains list by clicking on the
 **Change domains** link next to the checkbox. The **Allowed Domains**
 list will now appear. You can then add a domain to the list by typing the
 domain into the box underneath the list and clicking the **Add** button.

    ![Allowed domains list](/static/images/help/allowed-domains-list.png)

4. Domains can be deleted from the **Allowed Domains** list by clicking
 the **Delete** button next to a domain on the list.


    !!! warn ""
        Note: You must have at least one allowed domain if
         **Users restricted to** is enabled