District Office of Information Technology
Network Services and Computer Operations

IronMail

Anti-VIRUS & Anti-SPAM Email Firewall

SPAM: Identification and Tagging

Unsolicited and unwanted Email messages, SPAM, has become a significant problem for users throughout the district not only because of the nuisance, but because of malicious attachments, i.e., computer virus, that occasionally accompany them.  Messages that are received from the Internet are compared against a broad and comprehensive set of criteria to attempt to identify messages that are SPAM.  IronMail is a specialized server that detects SPAM by evaluating delivery characteristics of the message; header information, verifiable originator and forwarding server, message construction, and statistical information, i.e., how many of the same or similar messages being received throughout the Internet, and content, i.e., words and phrases which appear in SPAM.  It also scans every incomming message for the presence of computer virus.

IronMail determines the likelihood, or "confidence" that a message may be SPAM based on the aggregate characteristics related to the message.  Confidence-based detection results in a high degree of accuracy and few "false positives".  Iron Mail will drop the message when the confidence value is 50 or higher.  Messages that are delivered will have an X-esp line added to the header, which can be viewed by the recipient to see the overall score as well as the individual values of each component contributing to the overall score.

Why am I still getting SPAM?

The process of detecting SPAM is not fool-proof.  The characteristics of such messages is constantly changing.  As these characteristics are recognized, additional filtering rules are enabled to detect them.  Some unwanted messages will always pass through IronMail regardless of how effective the detection may be.

For those messages that continue to be received and are considered by the recipient to be SPAM, the best action is to simply delete them.  Many newer Email clients such as Outlook, Thunderbird and Eudora have incorporated junk-mail filtering algorithms that may further identify and isolate messages received by the client.