The Email Gateway Service provide the University with the following functions:
Border Email Handling This provides a check on all email coming into and exiting from the University.
Email Resilience The email gateways will temporarily store messages when the destination system is out of action or out of contact.
The Email Gateways are resilient with more than one system available in a flexible configuration. This is designed to reduce the impact of a Denial of Service attack (where someone tries to flood the University with traffic).
Email Addressing Supports the standard email addressing format (a.b.person@dundee.ac.uk) and ensures that email is delivered to correct destinations.
Email Virus Scanning Uses standard virus scanning tools to check email for known virus signatures.
Email Attachment Blocking Blocks email attachments which have a significant probability of causing damage to systems (desktop PCs are especially vulnerable).
Email spam Tagging Assess the probability of a message being spam (or unsolicited bulk email - UBE). Mark those so identified by adding the text "[spam ?]" in the subject line. This allows recipients to take automatic action to handle these messages. Because spam identification is not foolproof we recommend that the details of all messages identified as spam are scanned by the person receiving them before they are deleted (this does not mean that each one has to be opened or read - just checked).
Email is one of the most exacting IT related services because people now rely upon it for vital communications. The email gateways contribute to the reliability and effectiveness of email by use of sophisticated software and powerful computers.
The email gateways conduct safety checks on incoming email. For example:
Email messages cannot always be delivered - perhaps because the destination computer is undergoing maintenance, is faulty or because there is a network break somewhere. Our email gateways have a sophisticated system to keep hold of messages and deliver them at the first available opportunity. If delivery is no possible within a predefined time (currently 5 days), the sender will be notified (if possible).
Email can present significant processing loads on systems. All email handling systems are vulnerable to "Denial of service" attacks where someone uses the Internet to send an excessive number of messages in an attempt to prevent legitimate email being handled.
By having several systems, we spread the load and hope to cope with peaks beyond our normal levels. Unfortunately, there are no effective ways to prevent Denial of Service attacks as they can originate anywhere on the Internet.
Back to TopIt is inconvenient to everyone to have their email address change when they move department or change to a different computer system. Our standard email addressing system uses names of the form:
a.b.person@dundee.ac.uk
The email gateways automatically convert these standard (or formal) email addresses into specific ones which are used for delivery.
They also perform a reverse translation when email is sent out. This means that when a recipient replies to such an outgoing email, the correct address is available to them.
Back to TopIt is only email attachments which are vulnerable to viruses. Simple text email messages are safe.
Every email message is passed to a virus scanning system to check for any known signatures. If a virus is detected the message is quarantined or deleted.
If the message can be repaired by removing the virus then this is done and the message delivered.
Back to TopAttachments are files sent along with an email message. Many are innocuous but others can carry viruses. Lots of viruses (and worms) exploit attachments to spread - this has been a very effective mechanism for virus writers.
Our policy is to delete those attachments which are most likely to cause damage. Especially those which might cause damage before the recipient is even aware of the problem.
When we delete such an attachment we let the recipient know. Where possible, we also tell the sender. We do not do this where we believe the attachment has been sent because of a virus/worm attack.
If a legitimate attachment is blocked by this mechanism there are alternative routes you can use to transmit the file.
Our recommendations are to use a compression program (such as ZIP or STUFFIT) to encapsulate the file before transmission. This effectively renders the file harmless during transmission.
Alternatively you can use FTP or user something else that is not email.
Back to TopSpam is an ever increasing problem. In an attempt to manage the problem, the spam tagging service examines all messages and assesses the probability that they are spam.
Unsolicited commercial email (known as UCE or spam) is an increasing problem. This page describes how IT Services tries to identify spam so that you can choose what to do with it.
We use a variety of methods to identify spam messages, including the RBL (Realtime Blackhole List) service provided by JANET. There is a summary of that service on the JANET Web site.
When we receive an email, we perform checks to asses the likelihood of it being spam and allocate a weighting accordingly. If the weighting comes to 5 or above, we insert a "marker" into the Subject line of the message before we send it to you. You can instruct your email reader (such as Pegasus, Groupwise, eudora, Outlook, etc.) to look for this "marker".
You can choose to highlight the message, move it to a special folder, or even decide to delete it automatically.
It is notoriously hard to discriminate between spam and a legitimate message. We claim no special powers. This means:
The service is designed to highlight messages from sources known or suspected to send unsolicited email (known as spam).
We now check all incoming email to an @dundee.ac.uk address against a list of these known offenders. Should a message arrive from one of these hosts, we mark that message and allow the end-user to decide the fate of that message as it arrives at their email client. Email that looks suspiciously like spam is also marked.
Current policy does not yet allow us to delete these messages directly as they arrive.
We will never be 100% successful at identifying unwanted messages, but we hope to look at further enhancement by using other tools - time permitting.
Back to TopThere is no specific action required by email users because the services are automatically applied to messages as they pass through the gateways.
We offer specific advice about managing spam which we strongly recommend users to access.
Back to TopIt is important to us that you get the most out of the services we provide. If you have an issue, question or complaint about this service please let us know. You can do this by completing our short feedback form.
The email gateways cannot guard against all eventualities and email users must be on guard. Exceptions include:
We cannot detect all viruses or spam - we do what we can. New viruses will not have a signature which we can recognise. Spam can be disguised in many ways.
EMail messages can contain dangers which we cannot detect. Messages written in HTML (i.e. Web format) can have hidden functions such as confirming you have read the message thereby confirming your email address.
Some email will by-pass our systems and thereby not be subject to our checks.
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