With Outlook, or strictly at your ISP level?  I mean, with Outlook, Outlook
needs to be running the internet connection needs to be running, etc.  At
your ISP level, you don't need even your computer on.  On the other hand,
you'll need to ask your ISP how to do it, if it is even possible.  And they
might just say 'We have web based access to your mailbox, how is that not
good enough?'