How Tuffmail Spam Scoring Works
Tuffmail spam scoring is based on the SpamAssassin(tm)
Open Source software. Scoring may be enabled or disabled and score
thresholds set for an address, for a domain, or for the account.
Allow/Deny lists can be created for an individual address, for a
domain, or for the account.
An address or domain entry in an Allow list bypasses spam scoring
for senders that send very spammy looking email that is not spam.
There is a global Allow list that can be used also. This list
contains senders that are truly confirmed opt-in advertisers that
send email that looks just like spam.
An address or domain in a Deny list tags the email with an
X-Spam-Discard header. Email delivered to a Tuffmail mailbox stores
email with this header in the Discard folder. Discard folders are
automatically purged every 5 days.
There are two user configurable scoring thresholds. Email scoring
at or above the first threshold can be tagged with an X-Spam-Junkmail
header and/or the subject can be tagged with a prefix of your choice.
Email delivered to a Tuffmail mailbox stores email tagged with this
header in the Junkmail folder. The Junkmail folder is automatically
purged every 30 days.
Email scoring at or above the second threshold will be tagged with
an X-Spam-Discard header. Email delivered to a Tuffmail mailbox
stores email with this header in the Discard folder. Discard folders
are automatically purged every 5 days.
Scoring occurs before the final destination of the email is determined.
Email forwarded to a server outside the Tuffmail system can use the
headers to determine what to do with the email.
The average spam score is currently 13 with 95% of the spam scoring
5 or higher. 99% of the spam scores 4 or higher. 99.9% of the
non-spam email we see scores 4 or lower. This does not include
requested newsletters full of web bugs, unsubscribe links, and
special offers that look just like spam. The average non-spam score
is -5. Most all person to person email will score below 0.
The default thresholds are 6 and 13 and depending on what kind of
spam you are receiving and what newsletters you are subscribed to,
these settings will deliver almost all spam to the Junkmail or
Discard folder. Better results are achieved by adding newsletter
senders to an Allow list and setting the thresholds a bit lower.
The scoring results are added to the email headers when scoring is
enabled for an address or when we are sending all email through the
scoring system for testing. When testing, scoring headers are added
but the email is delivered as it would be if you have scoring
disabled.
Scoring headers look like this:
X-Spam-Status: Yes, score=28.7 threshold=5.0 X-Spam-Report: Content Analysis details: 1.3 X_PRIORITY_HIGH Sent with 'X-Priority' set to high 2.7 SUBJ_YOUR_FAMILY Subject contains "Your Family" 0.6 TO_MALFORMED To: has a malformed address 4.1 MSGID_SPAM_ZEROES Spam tool Message-Id: (12-zeroes variant) 0.5 X_MSMAIL_PRIORITY_HIGH Sent with 'X-Msmail-Priority' set to high 1.2 HTML_IMAGE_ONLY_02 BODY: HTML: images with 0-200 bytes of words 2.0 MIME_HTML_ONLY BODY: Message only has text/html MIME parts 5.4 BAYES_99 BODY: Bayesian spam probability is 99 to 100% [score: 0.9996] 0.1 HTML_MESSAGE BODY: HTML included in message 2.2 HIDE_WIN_STATUS BODY: Javascript to hide URLs in browser 4.1 MSGID_OUTLOOK_INVALID Message-Id is fake (in Outlook Express format) 2.5 RCVD_IN_DSBL RBL: Received via a relay in list.dsbl.org [<http://dsbl.org/listing?ip=80.202.114.125>] 1.0 FORGED_OUTLOOK_TAGS Outlook can't send HTML in this format 1.0 FORGED_OUTLOOK_HTML Outlook can't send HTML message only X-Spam-Check: Enabled X-Spam-Discard: Yes X-Spam-Score: 28.7 X-Spam-Flag: Yes
Examining the scoring headers can help you determine what scoring
thresholds to use.