Extension:LoginNotify/loginnotify seen net table

mysql> describe loginnotify_seen_net;
+-----------------+----------------------+------+-----+---------+----------------+
| Field           | Type                 | Null | Key | Default | Extra          |
+-----------------+----------------------+------+-----+---------+----------------+
| lsn_id          | int(10) unsigned     | NO   | PRI | NULL    | auto_increment |
| lsn_time_bucket | smallint(5) unsigned | NO   |     | NULL    |                |
| lsn_user        | int(10) unsigned     | NO   | MUL | NULL    |                |
| lsn_subnet      | bigint(20)           | NO   |     | NULL    |                |
+-----------------+----------------------+------+-----+---------+----------------+