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computing:accounts:email:spam [2007/10/30 12:20] – allancomputing:accounts:email:spam [2011/01/14 18:36] (current) – allan
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-====== Spam ======+====== Spam Control and Deterrence ======
  
 ===== What to do about Spam ===== ===== What to do about Spam =====
-  * There's not much we can do to prevent people from sending it to you +  * We do make best effort to prevent spam sent to you from being delivered 
-  * You can use our filtering service to reduce it, if you like (see below) +  * There's not much we can do to prevent attempts to send it to you; we can't follow up and investigate individual messages. 
-  * There's a lot more information at the OIT Spam information page and at CAUCE (Coalition against Unsolicited Commercial Email) +  * There's a lot more information at the [[http://www.oit.umn.edu/security/topics/spam/|OIT Spam information page]] 
 + 
 +===== Greylisting and blacklists ===== 
 + 
 +We run the OpenBSD [[http://www.openbsd.org/cgi-bin/man.cgi?query=spamd&sektion=8|spamd]] service to prevent or delay message delivery from suspect servers. In addition, systems which attempt to send messages to nonexistent accounts or defunct physics hostnames are temporarily blacklisted.  
 + 
 +You can view a list of messages which were blocked or greylisted (delayed) on your [[https://www.physics.umn.edu/resources/myphys/|MyPhys]] page. Delayed messages should normally arrive within about a half hour (although to some extent this will depend on the sending mail system), and once a message has been delivered, future messages from that source will have no delay.
  
 ===== Spam Filtering ===== ===== Spam Filtering =====
  
-We now run the SpamAssassin filter on all incoming messages to our mail system. SpamAssassin simply assigns each message a "score", based on the content.+We also run the SpamAssassin filter on all incoming messages to our mail system. SpamAssassin simply assigns each message a "score", based on the content.
   * Messages with a score of 5 or less are left alone   * Messages with a score of 5 or less are left alone
-  * Messages with a score between 5 and 8 have the text ****SPAM added to their subject line befrore being delivered. +  * Messages with a score between 5 and 10 have the text ****SPAM added to their subject line before being delivered. 
-  * Messages with a score over 8 are rejected. +  * Messages with a score over 10 are rejected (our system refuses to deliver them to you and the sender receives a bounce message). 
  
-However, we will be checking the results of our spam scoring over time, and shall probably revise some of these thresholds downwards.+==== Custom Filters ====
  
-You can change settings within your account to take further action based on this score, such as move messages to a different folder, or even delete them completely.+You can change settings within your account to take further action based on the spamassassin score, such as move messages to a different folder, or even delete them completely.
  
 These settings are made within the Physics webmail system. As an example, let's say you want to filter those messages with scores with 6 or higher, so they are placed into a separate folder instead of your INBOX. These settings are made within the Physics webmail system. As an example, let's say you want to filter those messages with scores with 6 or higher, so they are placed into a separate folder instead of your INBOX.
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   * Under Condition change the first drop-down box which says **To: or Cc** to **X-Spam-Level**   * Under Condition change the first drop-down box which says **To: or Cc** to **X-Spam-Level**
   * In the text box after contains enter <code>******</code> (that is, 6 stars)   * In the text box after contains enter <code>******</code> (that is, 6 stars)
-  * Under Action choose **Move message into** and select a folder name as the destination. //Don't choose the global "spam" or "notspam" folders, as this is not their intended purpose - see below for more on these folders.//+  * Under Action choose **Move message into** and select a folder name as the destination.
   * Under **Additional actions**, check **STOP: If this rule matches, do not check any rules after it.**   * Under **Additional actions**, check **STOP: If this rule matches, do not check any rules after it.**
   * Click **Add New Rule**   * Click **Add New Rule**
  
-===== Understanding SpamAssassin Scores =====+==== Understanding SpamAssassin Scores ====
  
 You can see the set of rules which triggered a spam tag for a particular message in the header "X-Spam-Status", and the list of SpamAssassin's default scores can be found here: [[spam_default_scores]] You can see the set of rules which triggered a spam tag for a particular message in the header "X-Spam-Status", and the list of SpamAssassin's default scores can be found here: [[spam_default_scores]]
  
-===== Training SpamAssassin ===== 
-Sometimes, SpamAssassin will misidentify a message, so that a message which is clearly spam receives a low score, or vice versa. 
- 
-You can help to train our mail server to recognise spam better by copying misidentified messages to the global "spam" or "notspam" folders on the mail server. 
- 
-<note important> 
-Before you try using this, read the instructions below carefully! 
-</note> 
- 
-  * Copy spam messages which spamassasssin failed to label as spam into the "spam" folder. 
-    * Don't copy any messages in here which already have **SPAM** in the subject - SpamAssassin already detected them! 
-    * Don't copy messages into here just because you didn't want them. We've found bulk emails from the University copied in here, as well as circulars from real companies with clear unsubscription directions; even physics-related mailing list material. None of these are spam - don't place them in here!  
-  * Copy regular messages which spamassasssin wrongly thought were spam into the "notspam" folder  
- 
-Both these folders are "write-only" - you can copy messages into them (for example, by dragging within Thunderbird), but you can't actually open the folders or read messages from them. 
computing/accounts/email/spam.1193764817.txt.gz · Last modified: 2007/10/30 12:20 by allan

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