How Does it Work?
Everyone's spam is tagged
All mail originating off-campus that passes through campus mail servers is scanned by a program called SpamAssassin to determine if it is spam. Mail that originates from an internal UCD IP address (169.237.x.x or 128.120.x.x) is not scanned. When a message is analyzed, it is "tagged" by adding one or more special lines to the "header" of that message.
The results of the spam analysis are added to the headers of the email message with lines similar to the following:
| X-Ucd-Spam-Score: |
6.251 (******) BAYES_80,HTML_MESSAGE,SARE_ADULT2,SARE_BETTERORG |
| X-Spam-Score: |
6.251 (******) BAYES_80,HTML_MESSAGE,SARE_ADULT2,SARE_BETTERORG |
The X-Ucd-Spam-Score holds a basic (or raw) spam score value expressed in points. Since even legitimate messages may contain some elements also found in spam, such as using HTML, mention of opt-out methods (for mailing lists), and the use of "adult" words and terms, messages must meet certain point thresholds before they are identified as spam by campus mailservers. The higher the score, the more attributes of spam the message possesses.The X-Spam-Score header will only appear when a message has a basic spam score of 5 or higher. Messages with a score from 5 to 14.9 are likely to be spam; messages with a score of 15 or more are virtually certain to be spam.
These headers are normally invisible to recipients unless the mail program is set to display full headers. They are used by UC Davis systems to determine which messages to filter as spam.
When messages are determined to be spam, analysis results will be appended to the body of the message that offer short explanations of each spam attribute found in the message, and each attribute's point value, as shown below:
SPAM: INVALID_DATE_TZ_ABSURD (4.0 points) Invalid Date: header (timezone does not exist)
SPAM: SUBJ_HAS_SPACES (2.6 points) Subject contains lots of white space
SPAM: FROM_HAS_MIXED_NUMS (0.3 points) From: contains numbers mixed in with letters
SPAM: EXCUSE_15 (0.6 points) BODY: Claims to be legitimate email
SPAM: EXCUSE_10 (0.3 points) BODY: "if you do not wish to receive any more"
For example, EXCUSE_15 is the code for a claim to be a legitimate message (a common spam characteristic), which added 0.6 points to its total spam score.
Filtering Spam
Campus filtering service
The University automatically attempts to reject spam for all campus addresses (those ending in @ucdavis.edu) where the spam score is 15 or higher. In addition, if you receive your email on one of the campus pop/color servers, messages with a spam score of 5 or higher are automatically moved to a UCD-spam folder on the server, and not delivered directly to your mailbox. Messages filtered as spam are automatically deleted after 14 days. To opt in to this filtering service, or change your existing UC Davis spam filter options, visit the IET Spam Filtering Settings page.
Viewing filtered messages
Messages filtered by the campus system are not viewable with a POP connection to campus mailservers, since filtered messages sent to your UCD-spam folder, not your Inbox. Filtered messages may be viewed using Geckomail, Pine, or any e-mail client application that supports IMAP.
Filtering Spam with E-Mail Clients
If you use a POP email program such as Outlook or Apple Mail and do not want the mail filtered by the UC Davis servers, there is another option. You can opt out of campus spam filtering by disabling filtering on the settings page, and have your own e-mail client perform this task. This way, all messages sent to you, including spam, will be downloaded and stored on your own computer. Instructions for setting this up are available for Outlook 2003 and Apple Mail, two popular e-mail clients. If your mail is forwarded to a departmental or external e-mail account, this would be one way to filter your spam.
Frequently Asked Questions
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How long will filtered spam be available on the server?
14 days.
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I use a POP mail program such as Eudora or Outlook. How can I access my UCD-spam folder?
The filtered message folders can be accessed via Geckomail.
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Why would I want to look at filtered messages? Why not just delete the spam automatically?
The highest-scoring messages are automatically deleted by default. There is a very small chance, however, that a legitimate message containing spam-like characteristics could be erroneously tagged as spam. It is recommended that you enable the option to receive weekly summaries via email. This way, you can read the weekly spam summary message to decide whether you would like to view any messages that were identified as spam.
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I received a message that I consider undesireable; I think it's spam! What should I do?
View the full headers of the message and if the message originated from a University IP address, forward the message with full headers to abuse@ucdavis.edu. Please note that the abuse team receives many such messages; if you don't receive a reply to your message, it doesn't mean your report was ignored.
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I did not receive a message that I consider desireable, I think it was tagged as spam! What should I do?
First, consider your options. Make sure you have engaged in the best spam-tagging and filtering solution for you. Campus systems will always add spam header information to messages, but whether or not you choose to filter tagged spam, and how you filter the messages, are ultimately up to you.
You can also display the message's full header information and forward a copy of the message, along with a description of the problem, to ithelp@ucdavis.edu.
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I have a Bulk Communication, it's approved, but how do I know how this will score?
If you are using the Campus's Bulk Email process through IET your email message will not be scanned by the campus spam filters. If you are sending a bulk message from an off-campus third party service, you should have them send you a test message and view the full headers to determine the spam score generated by the message.
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