Mail Filtering Rules
For the protection and convenience of users, mail received by DoIT mail servers or mail with EPO addresses is filtered. This process attempts to protect against viruses, spam, phishing, hoaxes, and other attacks. Certain limits on size and content are imposed on e-mail messages and attachments being sent and received from DoIT mail servers.
Incoming Mail: What Gets Scanned
The Stony Brook mail servers examine five major areas of a mail message before delivering it to your inbox.
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Virus, Spam and Malicious Code Signatures
The entire mail message is scanned by Symantec Mail Security for viruses and spam. If any part of a mail message or attachment yields a positive, the e-mail message is deleted. There is no notice to the sender or recipient. Right now, this constitutes about 70% of incoming e-mail. -
Attachments
All attachment names and extensions are examined. Attachments with certain names or extensions will be deleted and an indication that it was deleted will be put in the message back to the sender. Other attachment names may cause the entire message to be deleted without notification to sender or recipient. Generally, this is done to protect against certain scripts or programs not detected as viruses, but that might deposit malicious code on the target system. -
Subject Title
Certain subjects will cause the message to be deleted without notification. This is done to prevent phishing attacks and other hoaxes. -
From Address (Sender)
Certain sender names will cause the message to be deleted without any notification. Many hoaxes and "social engineering" attempts rely on using fraudulent sender addresses to give the message more value and importance to the end user.. -
Message Size
There is a practical limit on the size of a mail message as large messages may crash or slow down the mail transfer process. Size limits vary depending on which mail system you are using.
Outgoing Mail: What Gets Scanned
Outgoing mail is subject to some but not all of the above actions. In some cases outbound mail filtering is needed to catch messages that might come from a compromised work station. Outgoing mail is examined the same way as incoming mail for viruses, spam and malicious code. The same goes for attachments. No subject filtering or sender filtering takes place. There is a limit on the size of a mail message depending on the system you are using. Another consideration for outgoing mail is the number of recipients that can be addressed in one outgoing mail message. Most systems impose a limit. This too, varies depending on the system you are using.
Find out the filtering rules for your system below.
Filtering and the EPO
Addresses using FirstName.LastName@stonybrook.edu or sunysb.edu (EPO) will be scanned according to the rules of MS, even if its final address is something other than a DoIT mail server.