SQL Server : Backup to different machine

There was a question that I curious how to backup sql server database to different machine (using Universal Naming Convention path).
Now I find the explanation in the books online and a clue from some internet resources :-)
It is the login account that is used to start the sql server instance that matters.
When I choose Local System account, it doesn't require password, but it does not have network access.
To have network access, I use domain user account and restart the service. It now can access \\servername\folder that is accessible by the domain user account.