Postfix and bogofilter

[jim]

I think postfix/bogofilter is working good enough to tell how I did it.  I 
don't have procmail installed, so this is how I did it without it.  This is 
on a mailserver that handles mail for a small number of users.

1. Get postfix installed and running properly.

2. Get bogofilter installed and running properly from the command line.

3. Create a user, I used 'filter' as a username.  This user should not be able 
to log in, but does need a home directory.  I used '/home/filter'.

4. Put the bogofilter executable in /usr/sbin

5. Put the following script in /usr/sbin

#!/bin/bash

export PATH=$PATH:/usr/sbin
export HOME=/home/filter
cd $HOME

bogofilter -p | sendmail -i "$@"

6. In the master.cf configuration file for postfix, find the line that looks 
like:

smtp	inet   (some other stuff)   	smtpd

and add this line after it.

	-o content_filter=filter:

Be sure to include the ':' at the end of the line.

7. Append these lines to the end of the master.cf file:

filter    unix  -       n       n       -       -       pipe
  user=filter argv=/usr/sbin/filtermail -f ${sender} -- ${recipient}

8. Do a 'postfix reload'.

9. Now, anything bogofilter recognizes as spam will have a header that looks 
like:

X-Spam-Status: Yes, tests=bogofilter

and anything it doesn't think is spam will look like:

X-Spam-Status: No, tests=bogofilter

10. Even though bogofilter is now filtering your email.  It doesn't know what 
to look for to distinguish spam from real email.  Create two other mail 
accounts, one for spam and one for non-spam.  Anytime you receive spam that 
bogofilter doesn't catch, forward it to the spam address.  Anytime you 
receive good mail that bogofilter thinks is spam, forward it to the non-spam 
address.  Periodically, log on to the mail server and go to the directory 
where the spam mails are.  'su' as the user 'filter' and do a 'cat * | 
bogofilter -s'.  Delete all the spam files.  Then go to the directory where 
the good emails are and do a 'cat * | bogofilter -h'.  Then delete all the 
good emails.  Hopefully, the performance of bogofilter improves over time.

Bogofilter has a bug where the last line is sometimes duplicated using the 
'-p' option.