Greylisting is very useful to avoid most of the incoming spam on your mail server. The Qmail packages shipped on Dotdeb have built-in MySQL-based greylisting. Here is how to enable it…
Installation
First of all, be sure to have Qmail installed from Dotdeb with a version number greater than 1.03-37.dotdeb.1.
Then, since we’ll use a MySQL backend to share the greylisting database between several servers, be sure to have MySQL installed somewhere on your boxes.
In our example, we’ll create the database (we’ll name it relaydelay) and grant access to user@host with the password “password“. You’re free to change these values to fit your needs…
CREATE DATABASE relaydelay;
GRANT ALL PRIVILEGES ON `relaydelay`.* TO 'user'@'localhost' IDENTIFIED BY 'password'; |
CREATE DATABASE relaydelay;
GRANT ALL PRIVILEGES ON `relaydelay`.* TO 'user'@'localhost' IDENTIFIED BY 'password';
Then, we create the needed tables :
CREATE TABLE relaytofrom
(
id bigint NOT NULL auto_increment,
relay_ip char(16),
mail_from varchar(255),
rcpt_to varchar(255),
block_expires datetime NOT NULL,
record_expires datetime NOT NULL,
blocked_count bigint default 0 NOT NULL,
passed_count bigint default 0 NOT NULL,
aborted_count bigint default 0 NOT NULL,
origin_type enum("MANUAL","AUTO") NOT NULL,
create_time datetime NOT NULL,
last_update timestamp NOT NULL,
primary key(id),
key(relay_ip),
key(mail_from(20)),
key(rcpt_to(20))
);
CREATE TABLE dns_name
(
relay_ip varchar(18) NOT NULL,
relay_name varchar(255) NOT NULL,
last_update timestamp NOT NULL,
primary key(relay_ip),
key(relay_name(20))
);
CREATE TABLE mail_log
(
id bigint NOT NULL auto_increment,
relay_ip varchar(16) NOT NULL,
relay_name varchar(255),
dns_mismatch bool NOT NULL,
mail_from varchar(255) NOT NULL,
rcpt_to varchar(255) NOT NULL,
rcpt_host varchar(80) NOT NULL,
create_time datetime NOT NULL,
primary key(id),
key(relay_ip),
key(mail_from(20)),
key(rcpt_to(20))
); |
CREATE TABLE relaytofrom
(
id bigint NOT NULL auto_increment,
relay_ip char(16),
mail_from varchar(255),
rcpt_to varchar(255),
block_expires datetime NOT NULL,
record_expires datetime NOT NULL,
blocked_count bigint default 0 NOT NULL,
passed_count bigint default 0 NOT NULL,
aborted_count bigint default 0 NOT NULL,
origin_type enum("MANUAL","AUTO") NOT NULL,
create_time datetime NOT NULL,
last_update timestamp NOT NULL,
primary key(id),
key(relay_ip),
key(mail_from(20)),
key(rcpt_to(20))
);
CREATE TABLE dns_name
(
relay_ip varchar(18) NOT NULL,
relay_name varchar(255) NOT NULL,
last_update timestamp NOT NULL,
primary key(relay_ip),
key(relay_name(20))
);
CREATE TABLE mail_log
(
id bigint NOT NULL auto_increment,
relay_ip varchar(16) NOT NULL,
relay_name varchar(255),
dns_mismatch bool NOT NULL,
mail_from varchar(255) NOT NULL,
rcpt_to varchar(255) NOT NULL,
rcpt_host varchar(80) NOT NULL,
create_time datetime NOT NULL,
primary key(id),
key(relay_ip),
key(mail_from(20)),
key(rcpt_to(20))
);
We now have to put the appropriate settings in the /etc/init.d/qmail init script…
export MYSQLHOST="localhost"
export MYSQLUSER="user"
export MYSQLPASS="password"
export MYSQLDB="relaydelay"
export BLOCK_EXPIRE=5 # minutes until email is accepted
export RECORD_EXPIRE=600 # minutes until record expires
export RECORD_EXPIRE_GOOD=36
export LOCAL_SCAN_DEBUG=0 |
export MYSQLHOST="localhost"
export MYSQLUSER="user"
export MYSQLPASS="password"
export MYSQLDB="relaydelay"
export BLOCK_EXPIRE=5 # minutes until email is accepted
export RECORD_EXPIRE=600 # minutes until record expires
export RECORD_EXPIRE_GOOD=36
export LOCAL_SCAN_DEBUG=0
and in the /usr/sbin/greylisting-delete-expired :
MYSQLHOST="localhost"
MYSQLUSER="user"
MYSQLPASS="password"
MYSQLDB="relaydelay" |
MYSQLHOST="localhost"
MYSQLUSER="user"
MYSQLPASS="password"
MYSQLDB="relaydelay"
We can now relaunch Qmail and enable or disable the greylisting with a simple symbolic link :
/etc/init.d/qmail
ln -s /usr/bin/qmail-envelope-scanner /usr/sbin/qmail-envelope-scanner |
/etc/init.d/qmail
ln -s /usr/bin/qmail-envelope-scanner /usr/sbin/qmail-envelope-scanner
Usage
Example wildcard whitelists for subnets :
INSERT INTO relaytofrom VALUES (0,"127.0.0.1" ,NULL,NULL,"0000-00-00 00:00:00","9999-12-31 23:59:59",0,0,0,"MANUAL",NOW(),NOW());
INSERT INTO relaytofrom VALUES (0,"192.168" ,NULL,NULL,"0000-00-00 00:00:00","9999-12-31 23:59:59",0,0,0,"MANUAL",NOW(),NOW()); |
INSERT INTO relaytofrom VALUES (0,"127.0.0.1" ,NULL,NULL,"0000-00-00 00:00:00","9999-12-31 23:59:59",0,0,0,"MANUAL",NOW(),NOW());
INSERT INTO relaytofrom VALUES (0,"192.168" ,NULL,NULL,"0000-00-00 00:00:00","9999-12-31 23:59:59",0,0,0,"MANUAL",NOW(),NOW());
Example wildcard whitelist entry for a recieved domain or subdomain
INSERT INTO relaytofrom VALUES (0,NULL,NULL,"sub.domain.com","0000-00-00 00:00:00","9999-12-31 23:59:59",0,0,0,"MANUAL",NOW(),NOW()); |
INSERT INTO relaytofrom VALUES (0,NULL,NULL,"sub.domain.com","0000-00-00 00:00:00","9999-12-31 23:59:59",0,0,0,"MANUAL",NOW(),NOW());
