SharePoint Alerts Web Part Administration
Edit the page, select the web part and click the pencil icon (Edit web part), then General Settings. Only site administrators can change these settings.

Communications List — the mail and SMS connections the web part can use. Click a connection to edit it, or Create New Communication Settings to add one (see SMTP, SMS Adjustment and Clickatell SMS Gateway).
Site groups — members of the selected groups may create alerts for other users.
Show all alerts — show the alerts of all users in the list, not only the user’s own.
External Host Path — replaces the host part of the {sitelink}, {itemlink} and {itemurl} tags in e-mails, for example to give external users a public address.
Active Directory default connection
Site Settings → Virto Alerts and Reminders opens the Active Directory default connection settings page with the fields Fully qualified domain name, Account name, Password and WFE server.
