CREATE TABLE `greylist_relays` (
  `sender_host_address` varchar(15) NOT NULL default '',
  `create_time` datetime NOT NULL default '0000-00-00 00:00:00',
  `expire_time` datetime NOT NULL default '0000-00-00 00:00:00',
  `reason` varchar(128) NOT NULL default '',
  PRIMARY KEY (`sender_host_address`),
  KEY `expire_time` (`expire_time`)
) ENGINE=MyISAM;