- Right-click on the mailbox you want to change, selecting Options ....
- Slide the Sender Verification Threshold slider to the left. A good setting is to slide it to somewhere between the 51%-74% ranges.
- Press the Save button.
Users can add either Domains or individual e-mail Addresses to the Allowed Senders (or Blocked Senders) lists. To block allow an individual e-mail address: select the message with the address you want to allow in the From field, right-click on the message, select Spam Mail à Allow messages from this Address. Users can edit the Allowed and Blocked Senders lists by using the Go To à E-Mail à Edit Senders List dialog. The Allowed and Blocked Senders list are shared company wide so that users can benefit from other user's efforts to block bad e-mail and allow good e-mail.
TIP: View Sender Verification
You can check the Sender Verification value of current messages in your mailbox by turning on the column in the mail listing window. To do this: 1) Open the View à Settings à Configure ... dialog; 2) Check the Sender % column. Now that the Sender Verification score is showing in the e-mail table, you can sort by that column to see which messages fall below the new threshold that you are intending to set -- if you see any address and/or domains that should be allowed but are below the threshold, you will want to add the to the Allowed Senders by right-clicking on them and choosing the appropriate option.
Spam ProbabilityIn addition to Sender Verification, there is the Spam Probability Threshold. Using the same technique noted above, users can review the Spam % that is being applied to good and bad e-mails. Analyzing these values will allow users to adjust up or down their Spam Probability Threshold to better manage the sorting of Spam and non-Spam (good) e-mails.
The Spam Probability is set by the Spam Filtering Engine, a sophisticated Bayesian reasoning engine. This process takes into account the content of an e-mail message and rates its various characteristics to determine if it Spam or not. Some of the characteristics it looks for include:
- the underlying encoding used in the message,
- the number of misspelled words,
- the presence of hidden text,
- the number of recipients,
- the number of hyperlinks,
- the number of image links,
- and many other characteristics that may contribute to the possibility that a given message is Spam.