Jamroom has a setting for this. Open ACP > Modules > Users > Users > Global Config, go to the Site Options section and choose Site Privacy:
| Site Privacy | What visitors who aren't logged in see |
|---|---|
| Public (all pages visible) | Everything. This is the default. |
| Limited (site index and log in / signup only) | Your home page, and the login and signup pages. Any other page sends them to the login page. |
| Private (no pages visible) | A page saying This site is private and only visible to logged in users, with links to log in and to create an account. The login and signup pages still work. |
Logged-in members see the whole site either way.
To show visitors your own welcome page instead, use Limited and make your home page that welcome page:
Visitors see that page, and every other page asks them to log in. See the Site Builder chapter for pages and widgets.
Earlier versions of this page added a redirect to the skin's header.tpl. You don't need that any more: use Site Privacy. If your skin still has that change, remove it when you switch.