Karmasphere Labs - SMTP and Email Anti-Spam

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Email Server Plugins

MTAs can query karmaserver with the client IP address and envelope sender in order to identify spammers. They may also query karmaserver with URLs in the body to identify phishing and other forms of fraud. This page contains short instructions for each email client for which we have a plugin; fuller instructions are usually available inside the package.

Exim

Exim can talk to the karmad included in the Mail::Karmasphere::Client distribution from an ACL.

1. Install Mail::Karmasphere::Client.
2. Download karma.acl to your exim configuration directory.
3. Edit your exim configuration file (as shown below).
4. If you want karmad to be able to reject messages, edit karma.acl to uncomment the reject lines.
5. Start karmad.
6. Restart exim.

Find the ACL section, and include the karma.acl file.

begin acl # find this line
.include /etc/exim/karma.acl

Now you can insert into any ACL (commonly acl_check_rcpt):

deny    !acl          = karma_rcpt_acl

Full documentation from Exim is available here, although Exim frequently rearrange their documentation, so this link is likely to break.

Postfix

Postfix can use the karmad included in the Mail::Karmasphere::Client distribution as a policy daemon.

1. Install Mail::Karmasphere::Client.
2. Edit your postfix configuration file (as shown below).
3. Restart postfix.

Edit /etc/postfix/master.cf:

policy  unix  -       n       n       -       0       spawn
	user=nobody argv=/usr/bin/karmad

Edit /etc/postfix/main.cf:

smtpd_recipient_restrictions =
	...
	reject_unauth_destination 
	check_policy_service unix:/tmp/karmad
	...
policy_time_limit = 3600

Full documentation from Postfix is available here.

Sendmail

A sendmail milter written in C is available from subversion. These short instructions assume that you are using the M4 system for configuring sendmail. Fuller instructions are available in the README file in the distribution.

1. svn checkout https://svn.anarres.org/svn/repos/code/c/karmamilter/trunk/ karmamilter
2. cd karmamilter
3. ./configure
4. make
5. make install
6. Edit your sendmail.mc file and add the following line: INPUT_MAIL_FILTER(`karmamilter', `S=local:/var/run/milter/karmamilter.sock')
7. Rebuild your sendmail configuration using make, and install the new configuration file if necessary.
8. Restart sendmail.

SpamAssassin

A SpamAssassin plugin is included in the standard Mail::Karmasphere::Client distribution.

1. Install Mail::Karmasphere::Client.
2. Copy 26_karmasphere.cf to your SpamAssassin configuration directory (usually /etc/mail/spamassassin).
3. Customize the configuration file as desired.
4. If you use SpamAssassin with spamd, restart spamd.

Not Listed Here?

Karma clients are available for many languages; they are a starting point for building new software integrations. Choose a client library and write a plugin! If you contribute it to the mailing list, it can get included on this page.