Junk Mail Filters
The email filter system of IIS uses the open source
Sendmail+mimedefang+SpamAssassin+greylist, accompanying sophos for
email virus scan. Sophos is an anti-virus software purchased by
Academia Sinica. The virus pattern file is updated every hour. Since
2007 Sophos is replaced by CLAMAV. SpamAssassin is a junk mail filter
developed by apache.org. It gives every mail a weighted score based on
the characteristics of mails. If this score exceeds certain threshold,
the mail will be treated as junk. Since Feb 2007 GREYLIST is also
included for filtering. Virus Filter
If the system detects virus contained in a mail, a
notification will be sent to the designated recipient. The mail will
not be sent to the recipient. Currently zip files are not scanned.
Please be very carefull on the zipped file, especially if it contains
The system will discard the attachment of mail if
- Virus is detected
- File extension is exe, com, bat, or scr
The system detects spam based on the following rules. If
the mail is not sent in a standard format, it's easy to be detected as
Currently we add "** IIS-Spam **" in the subject field for the spam
without discarding them. If you use email clients, there's a filter
function that you can put all these spam to cirtain mailbox. However
with IMAP the function is not supported by OUTLOOK, but is supported by
NETSCAPE and MOZILLA.
- The sender is in the blacklist. The blacklist is retrieved from
the database on the Internet.
- The mail is forged to be outlook format.
Emails have any the following property will not be sent by
the mail server
If other research groups would like to reject all the mails coming from
non-IIS address, please contact the computer center.
- From is forged to be an IIS address
- To is forged to be an IIS address
- Recipient is all-users or researchers, but the sender is not
Users can set up their own rules by
logging to https://iiswww.iis.sinica.edu.tw/CCS/mailfilter/saSetup.php
- Weighted score
The system computes a weight score for each mail. Users can set the
threshold for rejecting the mails. For example:
||Accept the mails with score
|Accept but add the subject
|6.9 <= score < 15 will
be accepted but marked with **Spam**
||Reject the mails with score
The default is to reject all mails with
score larger than 6.9.
- White List From
Mails coming from the white list will always be accepted.
firstname.lastname@example.org (certain address)
*@iis.sinica.edu.tw (certain domain)
*.sinica.edu.tw (certain subdomain)
- Black List From
Mails coming from the black list will always be rejected.
The setting is similar to white list.