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485 E Main St.
Ashland, OR 97520
Phone: 541-488-9207
Hours: Monday - Friday 9am - 5pm
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Anti-Spam
Introduction to SpamUnsolicited Bulk Email (UBE), also known as spam, costs organizations and individuals billions of dollars each year. It consumes time and resources while delivering content of limited, if any, value. Among the primary tools of spammers are third-party email servers with open relays. This means anyone can send an email through the server to anyone else, even if neither the sender nor the receiver has an account on the server. Spam can also come from authorized users with accounts on a server.
To help control spam, Ashland Home Net email servers are configured to perform a variety of tests that eliminate unwanted email.
Anti-Spam
Heuristic spam detection uses feature-matching rules developed through years of experience to identify spam. By carefully applying these rules to incoming email, Ashland Home Net Anti-Spam assigns a numerical “score” to each message. This “score” determines the likelihood of a message being spam.
Bayesian classification is a machine learning process from the artificial intelligence (AI) community. It is designed to help a computer “learn” to identify wanted and unwanted email by analysing the headers, subjects and bodies of two groups of messages - those known to be spam and those known to be non-spam. Ashland Home Net applies this knowledge to help determine if new incoming messages are likely to be spam or non-spam. Bayesian classification becomes more and more accurate over time as it continually examines new messages. Ashland Home Net heuristics message scoring system is as follows:
A message is marked as spam and delivered if its score is greater or equal to 5.0, but less than 7.5
A message is rejected with scores greater or equal to 7.5
As an example, with a spam score threshold set to 5.0 and the rejection threshold set to 7.5, then any message with a spam score that is greater than or equal to 5.0 but less than 7.5 will be considered spam and the massage will have specific tag inserted into its Subject header. This tag also contains information about the message’s spam score, which can be use by message filters to search for it and filter the message accordingly. This is a simple method for automatically routing spam messages to a designated "spam" folder. Any message with a spam score greater than or equal to 7.5 will be rejected during the delivery process. Ashland Home Net will monitor the spam filter’s performance over time and refine both the spam and rejection thresholds to suit our needs.
Example MessageThe following is an example tag that will be inserted at the beginning of the Subject header of all messages that meet or exceed the required spam score threshold.
***SPAM*** Score/Req: 09.30/05.00 – E-mail Subject Header!
The following is an example message header processed by Ashland Home Net’s E-mail system. You would not normally see this when reading your e-mail, but it can be viewed; in Outlook by opening a message and then selecting VIEW and then OPTIONS from the menu; or within WorldClient by opening a message and then selecting "View Message Source" on the menu bar.
X-Spam-Status: Yes, hits=9.6 required=5.0
tests=BASE64_ENC_TEXT,DATE_IN_FUTURE_03_06,FORGED_MUA_OUTLOOK,
FORGED_YAHOO_RCVD,MISSING_MIMEOLE,OFFERS_ETC
version=2.54
X-Spam-Level: *********
X-Spam-Checker-Version: SpamAssassin 2.54 (1.174.2.17-2003-05-11-exp)
X-Spam-Report: ---- Start SpamAssassin results
9.60 points, 5 required;
* 0.8 -- BODY: Stop with the offers, coupons, discounts etc!
* 1.6 -- RAW: Message text disguised using base-64 encoding
* 0.9 -- Date: is 3 to 6 hours after Received: date
* 2.3 -- 'From' yahoo.com does not match 'Received' headers
* 0.5 -- Message has X-MSMail-Priority, but no X-MimeOLE
* 3.5 -- Forged mail pretending to be from MS Outlook
---- End of SpamAssassin results
X-Spam-Flag: YES
Subject: [***SPAM*** Score/Req: 09.60/05.00] Ionic air cleaners
X-Spam-Processed: ashlandhome.net, Mon, 04 Aug 2003 11:09:13 -0700
Our Spam filtering process - Incoming email is scanned by a security add-on component that is called Outbreak Protection (OP for short). OP is a service that receives updates about outbreaks of spam email and viruses. These updates are collated live statistical analysis of messages coming into servers running the OP module all around the world. This layer is designed to stop the most egregious and obvious spam. When a message does not pass the spam filter, the message is rejected with the SMTP status code 554 and the information "Sorry, this message looks like spam or phish to me."
- If a real person did send the message, the sender will get a bounce back email from their mail system saying that their message was rejected.
- The mail server is set to accept all messages for domains that pass SPF checks or DKIM checks. Messages from local users to local users are never rejected by this module.
- It is not possible for end users to control what email addresses are white-listed at this stage. Please visit our Support Center for information about contacting our support personnel.
- If the email passes the first spam filter, it then goes through another spam filter that is based on the SpamAssassin model, where email messages are weighted for spam like characteristics. At the end of the weighing process:
- If the message is from someone in the user's address book 100.0 points are subtracted from the spam score.
- Contacts are automatically added to the user's address book when they the send email to them.
- Users can add email addresses to their address book at the web interface
- If the message has a weighted score between 0 and 4.9, the message appears in the user's inbox with no modification
- If the message has a weighted score between 5.0 and 7.4, the message appears in the user's inbox with the text ***SPAM*** added to the front of the subject and additional header with the spam score added to it.
- If the message has a weighted score greater than 7.5, the message is returned to the sender from our mail system with an SMTP status code fo 554 and the text "Sorry, this message looks like spam or phish to me."
If you are having trouble with the Spam filtering, please use our Support Center to find out how to contact us.
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