It would be very nice when managing permissions for a user to have the ability to set the “Host” field in the “mysql.db” table. Currently the Host value just gets some sort of default from the mysql.user table but the user table could have multiple entries for the same “User”. Basically their does not seem to be a way to make use of the “mysql.host” table and give custom permissions for a host or give multiple hosts permission to the database by leaving the host field blank in the db table. Right now I have to modify the tables myself to make any permission changes, since we give multiple hosts access through the host table.
See the following link to the mysql manual about how the permissions work.