using require

hi all, i have my web site working something like this: in every php script i have require(auth.php). this auth.php has my connection to my postgresql server and database along with some other stuff i need for the user to be authenticated to my web site. when i log on, this auth.php connects to the dbserver and checks if my username and password are stored and then i go to a home page. my connection is stored in $dbh. what happens when i start moving through all these web pages (php scripts), each requires auth.php, with respect to the connection? is a new connection established for every web page i go into that uses my $dbh for querying purposes or is it the same connection i originally made when i first logged into the web site? any info will be highly appreciated!! thanx.