The CLIENT? As far as I know, you have to be logged in with Steam in order to run the game clients. That's by design - it's how Valve can make sure you're not running a game you don't own.
I'm not certain but I would say 'no'. Otherwise, it would just be too easy to pirate Steam games.
EDIT: Just noticed in the title you say 'Ded. Server'. Are you referring to 'Client' as in a customer?
I'm not certain but I would say 'no'. Otherwise, it would just be too easy to pirate Steam games.
EDIT: Just noticed in the title you say 'Ded. Server'. Are you referring to 'Client' as in a customer?