Server-Manager is only accessible from within the local network.
That is correct to a point ... as a default it's only accessible internally ... But ... you can open it up to external as well as thats how I do my test units.
Even if you open it up to external usage it still asks for user/password.
One trap that ppl fall into is when once you access the server-manager page and close the internet browser ... then re-open it ... it won't as you for the user/pass every time ... once it has let you in it seems to let you in again without asking.
This is not an SME problem ... I think it's just the caching or someting like that of the internet browser.
Someone with more experiance within that area could clarify it a bit more.
Regards,
Tib