That's right. I do not have any rules defined. But what shall be the difference? Whether I define the rules before in the template or if I do that manually in the manage site detail screen. The result is the same. The expression localhost that will be needed as standard term in the DB are not be generated. I get the Server IP instead.

Till that everything are generated without problems: the DB user, the DB itself, the DB password. Only the hostname that is needed for permissions is wrong.

If you want to force the DB Host, I think this is possible when you edit the "multisites.cfg.php" files as described in the users manual p14