Difference between revisions of "Spam Mail Filter"

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All the user's suspected spam is put in a personal mail file—''/cs/spam/'''login''''' (e.g. ''/cs/spam/george'').
 
All the user's suspected spam is put in a personal mail file—''/cs/spam/'''login''''' (e.g. ''/cs/spam/george'').
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=== Viewing in Pine ===
  
 
In order to view the folder, the user can do:
 
In order to view the folder, the user can do:
  pine -f /cs/spam/login
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  pine -f /cs/spam/'''login'''
 
E.g.
 
E.g.
 
  pine -f /cs/spam/george
 
  pine -f /cs/spam/george
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=== Viewing in Thunderbird or other IMAP clients ===
  
 
If you use IMAP, you can access the spam folder from your mail program by creating a link from ~/imap.mbox to the spam folder:
 
If you use IMAP, you can access the spam folder from your mail program by creating a link from ~/imap.mbox to the spam folder:
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Note that each message in this file will have an extra header, <tt>X-Spam-Reason</tt>, explaining why it was caught.
 
Note that each message in this file will have an extra header, <tt>X-Spam-Reason</tt>, explaining why it was caught.
  
== Legitimate Mail in Spam Folder ==
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== Legitimate mail in spam folder ==
  
 
Sometimes the heuristic spam-catching algorithm errs and legitimate e-mail is caught in one's ''spam folder''. In such a case, one should either bounce ('b' in Pine) or forward the caught message to the address '''notspam@cs''' so that the spam database will correct itself. Note that this is an automated address so no human will read the contents of the message meant to you.
 
Sometimes the heuristic spam-catching algorithm errs and legitimate e-mail is caught in one's ''spam folder''. In such a case, one should either bounce ('b' in Pine) or forward the caught message to the address '''notspam@cs''' so that the spam database will correct itself. Note that this is an automated address so no human will read the contents of the message meant to you.

Revision as of 11:15, 26 November 2006

Personal spam folder

All the user's suspected spam is put in a personal mail file—/cs/spam/login (e.g. /cs/spam/george).

Viewing in Pine

In order to view the folder, the user can do:

pine -f /cs/spam/login

E.g.

pine -f /cs/spam/george

Viewing in Thunderbird or other IMAP clients

If you use IMAP, you can access the spam folder from your mail program by creating a link from ~/imap.mbox to the spam folder:

mkdir -p ~/imap.mbox && ln -s /cs/spam/login ~/imap.mbox/Spam

You can then access the spam folder as a mail regular folder in the "#imap.mbox" namespace.

Note that each message in this file will have an extra header, X-Spam-Reason, explaining why it was caught.

Legitimate mail in spam folder

Sometimes the heuristic spam-catching algorithm errs and legitimate e-mail is caught in one's spam folder. In such a case, one should either bounce ('b' in Pine) or forward the caught message to the address notspam@cs so that the spam database will correct itself. Note that this is an automated address so no human will read the contents of the message meant to you.

In addition to updating the global database, you should put the sender address of the legitimate e-mail in your ~/.nospam personal exception database descibed in the next section.

Personal exception database

Since legitimate e-mail can sometimes be caught in /cs/spam/login , the user can create a personal exception database ~/.nospam with a list of sender addresses to pass through to the user's main mail inbox without being put in /cs/spam/login —note that the sender address can be extracted from the Return-path: header of the message (visible in full header mode).

Example contents of ~/.nospam :

haim@eng.tau.ac.il
*@wildnose.com
*@*.huji.ac.il
jody@*
jay@natlib.com
melody@math.gmu.edu

The above ~/.nospam file allows both individual addresses such as jay@natlib.com and groups of addresses such as all users from the wildnose.com domain and all users in subdomains of HUJI plus the login jody from any domain.

An entry of '*' (asterisk) will cause all suspected spam to pass through to your regular mailbox effectively disabling spam filtering.

Example:

echo '*' > ~george/.nospam

Spam folder cleanup

Any message left for more than 30 days in /cs/spam/login will be automatically deleted.

Hint: if you are going away for more than a month, it's a good idea to disable spam filtering (as explained above) during that time in order to avoid losing legitimate messages caught in the spam filter.

Spam e-mail that isn't caught

Since the spam-catching algorithm is heuristic, it doesn't catch all spam and some spam e-mailings manage to get through. If spam reaches your regular mailbox (and, of course, you haven't turned off spam filtering in your ~/.nospam file), then you should bounce ('b' in Pine) or forward the spam message to the address spam@cs to update the global spam database.