SPAM

To better combat spam and phishing attacks, a mail gateway has been introduced for all mail boxes at the Technical Faculty (known as Proxmox Mail Gateway).

Spam Quarantine Box (Proxmox Mail Gateway)

Recognized spam and phishing emails are not delivered to your mailbox but are instead held in quarantine, where they are automatically deleted after 30 days. In the Quarantine Box, these emails can be read, deleted, forwarded to your mailbox, whitelisted, or blacklisted.

Spam Report and Web Access to Quarantine Box

Currently, an information email is sent daily to your mailbox if new spam/phishing emails have been received in quarantine within the last 24 hours (if none have been received, no information email will be sent). The links in this information email take you directly to your Quarantine Box.

The Quarantine Box can also be accessed at any time via a web browser at https://spam.techfak.net/quarantine. You can log in as follows:

Field	Value
User name	login@techfak.de
Password	service/mail password

Interface

Button	Description
Toggle Raw	Display the source code of the selected email.
Toggle Spam Info	Display spam evaluation information for the selected email.
Download	Download the selected email as a .eml file.
Whitelist	Add the sender(s) of the selected email to your personal whitelist. This means future emails from this sender will not be treated as spam and will be delivered directly to your inbox. Also delivers the selected email to your inbox.
Blacklist	Add the sender(s) of the selected email to your personal blacklist. This means future emails from this sender will be immediately deleted and not quarantined or delivered to your inbox. Also deletes the selected email.
Deliver	Deliver the selected email to your IMAP inbox.
Delete	Permanently delete the selected email.

Not seeing all emails?

By default, you only see emails from the last 7 days. To also display older emails (up to 30 days in the past), the date filter must be changed:

Whitelist

Here, addresses and domains can be whitelisted, meaning that emails coming from these addresses and domains will be delivered directly to your mailbox without undergoing spam checks.

Examples:

Addresse	Description
*@gmail.com	All emails sent by senders whose addresses end with @gmail.com.
*uni-bielefeld.de	All emails ending in the domain area uni-bielefeld.de, e.g. melanie.muster@techfak.uni-bielefeld.de, newsletters@lists.techfak.uni-bielefeld.de, etc.
melanie-muster@vertrieb-xyz.de

Blacklist

Here, addresses and domains can be blacklisted. This means that emails coming from these addresses and domains will be deleted directly and irretrievably without undergoing spam checks.

The entries are created in the same way as for the whitelist (see above).

Disable Quarantine

If the quarantine feature is not desired and all emails should be delivered to the mailbox, you can whitelist all emails. To achieve this, simply add the address *@* to your personal whitelist:

Emails will still be analyzed for spam and can be sorted based on their Spam Level. The filters can most easily be added or modified in our webmailer (see the next section).

Email Marking headers

Based on this analysis, each email is assigned a Spam Score, which ranges from 0 to 15. A small score indicates that it is very unlikely to be spam. Emails with a score of five or higher are marked as spam, and those with a score of 15 or higher are rejected outright.

Emails are marked with specific headers to indicate their spam status:

Mail Header	Content (Example)	Meaning
X-Spam	yes	This email is probably spam. (This flag is set if the score is above 6.)
X-Spam-Level	*****	Score, coded as * for each whole number.
X-Spam-Info	Spam detection results: 5 BAYES_99 3.8 Bayes spam probability is 99 to 100% BAYES_999 0.2 Bayes spam probability is 99.9 to 100% HTML_IMAGE_ONLY_16 1.199 HTML: images with 1200-1600 bytes of words HTML_IMAGE_RATIO_02 0.001 HTML has a low ratio of text to image area HTML_MESSAGE 0.001 HTML included in message HTML_SHORT_LINK_IMG_2 0.603 HTML is very short with a linked image T_TVD_MIME_EPI 0.01 -	detailed rating

Filtering Based on X-Spam-Level

You can filter emails based on their spam scores using rules in your webmail. For example:

If the X-Spam-Level header contains at least file *, the mail is moved to Spam.