few securiry questions

hi there,I'm migrating from MySQL to PgSQL and
I have few questions on PgSQL securiry:
  1. How can I forbid to some users to create tables
in some databases which they can acccess.
  2. How can I GRANT/REJECT some privileges on all
objects in a database TO/FROM some users, since i
can't type "GRANT ALL ON * TO SOMEUSER;" in PgSQL. Is
there any functional analog?
  3. How can I reject to some users connections to
some databases from any host using password
authentication?
  4. Why this pg_hba.conf does not alow uses from
192.168.200.X to connect to the databases with message
telling that there was no entry for 192.168.200.x in
pg_hba.conf?
# pg_hba.conf

local  all                                   trust
host   all    0.0.0.0          0.0.0.0       reject
host   all    192.168.200.0    255.255.255.0 password

Thanks in advance!

Rumen


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