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(NOTE: this is part of the “An Anti-Spam gateway” series)

Go to the amavisd-new site and download the latest version (2.3.3 at the time of writing). Uncompress it somewhere, then copy amavisd to /usr/local/sbin (for instance), and amavisd.conf to /etc.

Edit the /etc/amavisd.conf file. Add the following lines to the end:

$daemon_user = ‘amavis’;
$daemon_group = ‘amavis’;
$mydomain = ‘YOURDOMAIN’; # replace with your own domain, of course
$virus_quarantine_method = ”;
$spam_quarantine_method = ”;
$banned_files_quarantine_method = ”;
$bad_header_quarantine_method = ”;
$sa_tag_level_deflt = -202.0;
$sa_tag2_level_deflt = 8.31;
$sa_kill_level_deflt = 50;
$sa_dsn_cutoff_level = 50;
$mailfrom_notify_admin = “YOUR EMAIL”; # add \ before the @, as in cats\@allyourbase.com
$mailfrom_notify_recip = “YOUR EMAIL”; # add \ before the @, as in cats\@allyourbase.com
$mailfrom_notify_spamadmin = “YOUR EMAIL”;# add \ before the @, as in cats\@allyourbase.com
$final_virus_destiny = D_DISCARD;
$final_banned_destiny = D_DISCARD;
$final_spam_destiny = D_DISCARD;
$final_bad_header_destiny = D_PASS; # many badly configured servers out there
$warnvirusrecip = 1;
$warnbannedrecip = 1;

(a few lines may have wrapped around in the above. They all start with “$“)

Create the following directories, making sure they belong to user and group amavis:

/var/amavis/tmp
/var/amavis/var,
/var/amavis/db

Run amavisd, and check if it’s listening in port 10024. If not, there should be some error message telling you what the problem (in /etc/amavisd.conf) is.

We’re almost done, now. Next: configuring Postfix to work with amavisd-new.

(NOTE: this is part of the “An Anti-Spam gateway” series)

Thought I’d forgotten about this one, didn’t you?

Ready to make SpamAssassin actually use MySQL for the bayes database?

Start by creating the database itself:

mysql
CREATE DATABASE bayes;
GRANT ALL PRIVILEGES on bayes.* TO bayes@localhost IDENTIFIED BY 'password';
GRANT ALL PRIVILEGES on bayes.* TO bayes@10.0.0.1 IDENTIFIED BY 'password';
EXIT

changing password to something else, of course

Next, I know you’ve already installed SpamAssassin using CPAN, but go to www.spamassassin.org and download it manually; you’ll be needing a file from the distribution, and while it should still be in /root/.CPAN, it’s simpler this way. Uncompress the .tar.gz and go to the sql/ directory. Then type:

mysql -u bayes -p < bayes_mysql.sql

It’ll ask for a password, which is the one you used when creating the database.

Now, edit the file /etc/mail/spamassassin/local.cf. Add the following lines:

bayes_store_module Mail::SpamAssassin::BayesStore::MySQL
bayes_sql_dsn DBI:mysql:bayes:localhost
bayes_sql_username bayes
bayes_sql_password password

(again, replace password with the proper one.)

SpamAssassin is now configured to store bayes data on MySQL. Wasn’t too hard, was it?

(NOTE: this is part of the “An Anti-Spam gateway” series)

Vipul’s Razor is a piece of software for accessing a large database of spam messages. By installing it, and configuring SpamAssassin to use it, you can, among SpamAssassin’s other tests, see whether a particular message has been previously reported as spam by other people. You can also report messages yourself.

It’s not a perfect system, but the best way to use SpamAssassin is by combining several methods of checking spam. This is simply one more.

Note: although I have previously said that I won’t be offering different alternatives, as this is a “recipe”, for Razor I’ll make an exception. If you don’t want to use it, simply skip this part and move on to the next.

Continue reading ‘An Anti-Spam gateway #6: Razor’

(NOTE: this is part of the “An Anti-Spam gateway” series)

Continuing the Postfix configuration… Edit the /etc/postfix/main.cf file.

Look for, and change according to your configuration, the following options:

myhostname (should be your machine’s name)

myorigin (probably $mydomain)

mynetworks (your network(s), possibly 10.0.0.0/24 in this case)

relay_domains (should be, of course, your domain(s))

bounce_notice_recipient, delay_notice_recipient, error_notice_recipient, policy_notice_recipient (change them all to postmaster@yourdomain, assuming that address exists or is an alias to an existing one - possibly yours, and replacing yourdomain with your domain, of course)

Change the smtpd_client_restrictions option to:
  smtpd_client_restrictions = permit_mynetworks,
   reject_rbl_client relays.ordb.org,
   reject_rbl_client sbl.spamhaus.org,
   permit

Change smtpd_helo_required to yes. Mail servers should learn to behave. Besides, it’s bulk spam senders that normally don’t.

Now, save that file, and edit /etc/postfix/transport. Except for the comments, it should be changed so that it only has this line:

*       smtp:10.0.0.2

(remember? that’s the real mail server’s address)

Leave the editor, then do the following: postmap /etc/postfix/transport, to update the transport.db file.

Now, test it. Yes, when you start it (postfix start), if everything went well, it should already be working as a non-filtering gateway. Assuming, of course, that you configure your firewall so that mail from the outside (to port 25) is delivered there, and that it can connect to the real mail server, and that the latter accepts mail from the gateway.

When it’s working, go to the next part of the series.