Filtering SPAM

The recently installed mailserver allows us to run a very aggressive mail filter, SpamAssassin. Currently, an older, less effective filter is being applied globally to all incoming e-mail. In the near future, we will shut it off and the decision to use SpamAssassin will be left to the individual user. We highly recommend that you use it to reduce the amount of unsolicited commercial e-mail that you receive.

To enable the filter, simply create a file named .procmailrc in your home directory containing one of the following sets of lines:

Allow spam to enter your inbox with its subject line tagged with the string "*****SPAM*****".
```
:0fw
| /usr/bin/spamc
```
Send e-mail tagged as spam to a folder named spam under your mail/ subdirectory. You can then view it at your leisure. Be sure to clean it out regularly, because it may consume vast amounts of disk space in no time at all!
```
:0fw
| /usr/bin/spamc

:0:
* ^X-Spam-Status: Yes
spam
```
Same as above, but anything tagged as spam is discarded in the system trash can, /dev/null.
```
:0fw
| /usr/bin/spamc

:0:
* ^X-Spam-Status: Yes
/dev/null
```

Depending on your needs, you may or may not want to read mail that gets tagged as spam. There's a slight possibility that SpamAssassin could tag some legitimate e-mail as spam, a condition referred to as a "false positive," and this may be a deciding factor in whether or not you choose to use the filter and which of the three options is appropriate. If you want to disable the SpamAssassin filter, simply place a comment '#' character at the beginning of each of the SpamAssassin lines in your .procmailrc file (alternatively, just remove the file).

Note, if you have your e-mail forwarded from your math.tamu.edu account to some other address, this filter will not work.

You can also specify some of your own SpamAssassin rules in a file named $HOME/.spamassassin/user_prefs. Create the directory and the file with world-read permissions.

cd $HOME
mkdir .spamassassin
chmod a+x .spamassassin
cd .spamassassin
touch user_prefs
chmod a+r user_prefs
edit the user_prefs file with your preferred editor
-=-=-=- cut here -=-=-=-
# Blacklist - deny
blacklist_from user1@baddomain1.com user2@baddomain2.com *@baddomain.com

# Whitelist - allow
whitelist_from okuser1@okdomain1.com okuser2@okdomain.com *@okdomain.com

# Optional - required hits. System-wide default is 5.0.  Increase
# to soften spam control and reduce possibility of false positives.
required_hits 5.0
-=-=-=- cut here -=-=-=-

In addition to SpamAssassin, we maintain a blacklist of known spam domains from which we reject connections. We also bounce any e-mail containing nonprintable characters in the Subject line and any message containing an EXE, PIF, or COM attachment (to block viruses). These filters are applied globally, for all users, before any user-defined filters (e.g., SpamAssassin) are called.

Last update: 16Sep2002