How to insert an IP-address into an inet column in PostgreSQL?
It seems pretty easy:

postgres=# create table inet_test (address inet);

CREATE TABLE

postgres=# insert into inet_test values ('192.168.2.1');

INSERT 0 1

postgres=# insert into inet_test values ('192.168.2.1/24');

INSERT 0 1

postgres=# select * from inet_test;


 address
----------------
 192.168.2.1
 192.168.2.1/24
(2 rows)