disallow remote root / allow remote root by key

[Zbigniew Szalbot]

Hello,

I wonder if it is possible and if so how to go about the following.

Server - Remote root login is disallowed but I need to fetch snaphosts 
produced by rsnapshot and for this I need remote root access.
Backup machine on a dynamic IP - connects to server using key-based 
authentication. Can this machine (and only this machine) log in remotely 
as root?

Is there a better way of handling this?

Thanks!

-- 
Zbigniew Szalbot
www.lc-words.com