Restrict user email addresses to certain domains
Note: This feature can only be controlled by organization administrators.
Zulip allows organization administrators to block new users from signing up who are not in their organization. The administrator can accomplish this by restricting users to have email addresses only from the organization's domains.
Restricting user email addresses to certain domains can be enabled or disabled with the Users restricted to (allowed domains) checkbox in the Joining the organization section.
The allowed domains will be listed after the Users restricted to next to the checkbox.
Domains can be added to the allowed domains list by clicking on the Change domains link next to the checkbox to reveal the Allowed domains list. You can then add a domain to the list by typing the domain into the box underneath the list and clicking the Add button.
Domains can be deleted from the Allowed domains list by clicking the Delete button next to a domain on the list. However, you must have at least one allowed domain if the Users restricted to option is enabled.
Once you have made all your changes, exit out of the Allowed domains list by clicking the x () icon in the top right-hand corner of the Allowed Domains list.
Click on the Save changes button to save any changes you made to your organization settings.