GS> I see a use case for of generating addresses based on a sequence or some
GS> primary key from the database.
GS> Something like
GS> CREATE SEQUENCE hosts_ip_seq MAXVALUE 65536;
GS> ALTER TABLE hosts ALTER ip SET DEFAULT '10.0.0.0/16'::inet + nextval(hosts_ip_seq')
hmm, not quite good idea - SEQUENCEs, by design, does not rollback next
value on transation rollback, so you'll have holes on address range when
other values will break some constraints or concurrent sessions
appears.