Email

Overview

MTL offers users both secure POP/IMAP services for reading e-mail and secure SMTP Authentication for sending e-mail. All incoming and outgoing messages that travel through the MTL mail servers are scanned for viruses and other dangerous attachments/content as well as being marked with a spam tag if the message may be of a suspicious or junk/spam nature. In addition, to protect MTL from spam and/or being blamed for sending spam to the rest of the world, all e-mail that is sent through the MTL mail servers from outside MTL (e.g. from your home) and destined for an outside e-mail address (e.g. user at company.com) is required to be sent through a secure authenticated connection.

As mentioned above, all messages going through the MTL mail system are scanned. Messages that are found to contain computer viruses are not delivered and instead are quarantined. Other messages that contain possibly dangerous attachments/content are cleaned, with said attachments/content being removed and replaced with an informative message regarding what was removed and why. If this occurs, the original unaltered message is also copied into the quarantine area. The cleaned message is then delivered to the recipient while the sender also gets a message stating that the attachment/content was removed and why. In addition to virus and attachment/content scanning, MTL also does spam tagging where each message is assigned a spam score based on the system's educated guess as to the probability that the message is spam.  If a message’s spam score exceeds a certain threshold it will be automatically quarantined and not delivered to the recipient.  All other messages are delivered to the recipient but can optionally be filtered into a special spam folder if the user chooses to do so.

E-mail Configuration

MTL e-mail services are only available to MTL users. You can use MTL MUMMS to manage your MTL information including your e-mail settings. Users who don't reside within MTL or don't work for faculty that are directly affiliated with MTL are typically restricted to forwarding their MTL e-mail to another account and do not get full MTL e-mail privileges.

If you have full e-mail privileges and would like to use MTL e-mail then you can use the below settings as a guideline to set up your e-mail client. Each e-mail client will vary on the specific location where these settings are entered. Some will call them Tools, Preferences, Options, etc. but the key settings you will need are:

  • Account Type: IMAP
  • Incoming Server Name: mtl-pobox.mit.edu
  • Incoming Server Port: 993
  • Incoming Server Connection: SSL/TLS
  • Incoming Server Authentication Method: plain text MTL password
  • Outgoing Server Name: mtl.mit.edu
  • Outgoing Server Port: 465
  • Outgoing Server Connection: SSL/TLS
  • Outgoing Server Authentication Method: plain text MTL password

Note that you are required to authenticate to MTL before you can send mail through the outgoing mail server.

If you need help entering these settings in your specific e-mail client, please send mail to mail-problems [at] mtl.mit.edu.

E-mail Forwarding

Enabling forwarding allows a user to forward all their MTL e-mail to another valid e-mail address (e.g. their MIT Athena address). Users who do this will then be required to read their MTL e-mail using the aforementioned e-mail account.

You can now change your MTL Forwarding settings on-line by going to MTL MUMMS and logging in. Once there you can click on 'View Your E-mail Settings' in order to view/change your current MTL e-mail settings.

Spam Filtering

IMPORTANT NOTE: If you forward your MTL e-mail to your MIT e-mail account, then please read no further. Instead, you need to refer to MIT's instructions on spam filtering.

After an e-mail has run through the MTL message scanning service, it will be put through the MTL spam tagging service and be tagged with a spam score.  This score is not a number but a sequence of 's'es where the higher number of 's'es means that the message has a higher probability of being spam or junk e-mail. This spam score is attached to the header of each possible spam message. Users can then opt for the MTL mail server to redirect messages, that exceed a certain MTL spam threshold, to a special spam filter folder (this folder is called mtl-spam-filter) in their IMAP folders directory. Please see the next section on how to set your MTL spam threshold.

You can change your MTL Spam settings on-line by going to MTL MUMMS and logging in. Once there you can click on 'View Your E-mail Settings' in order to view/change your current MTL e-mail settings.

Spam Scoring and Settings

As mentioned above, the MTL spam tagging service adds a header to each e-mail that represents its spam score.  This header line contains a sequence of 's'es where the higher number of 's'es means that the message has a higher probability of being spam or junk e-mail. So, when you set your MTL spam threshold level, the higher the number you choose, the less aggressive your spam filtering will be. If you choose a lower number, then the more aggressive the filtering will be.  For example, if you choose a Custom Setting of '7', then any e-mail with spam headers that contain a sequence of 7 or more 's'es will be filtered into your mtl-spam-filter IMAP folder. If you do not understand what all of this means then it is highly recommended that you accept the default setting of 'Medium' when you set up your MTL spam filtering.  If you then decide that this is either too aggressive or too lax, you can always go back and change either setting.

Effectiveness of Spam Filtering

What and what is not spam is very hard to determine and can sometimes be a personal preference. This means that it is inevitable that some spam will get through even the most sophisticated filtering mechanism. If you have turned on filtering but are still getting a lot of spam messages in your INBOX, then you can try to increase either spam filtering threshold if it is currently set to a lower score threshold (e.g. if your current setting is 9, you can try and raise your setting to 6). While raising your spam filtering level may capture more spam, it may also increase the number of legitimate e-mails that are mistakenly marked as spam. Please see the next section regarding the downside to setting the score threshold to an overly aggressive level.

False Positives and MTL Spam Filtering

What and what is not spam is very hard to determine and can sometimes be a personal preference. This means that it is possible that some legitimate e-mail will be mistakenly put into your MTL spam filter folder even by the most sophisticated filtering mechanism. If you have turned on filtering and are getting legitimate e-mails being placed into your mtl-spam-filter folder, then you can try to decrease your spam filtering level if it is currently set to a high (i.e. aggressive) score threshold (e.g. if your current setting is 6, you can try and raise your setting to 9). While lowering your spam filtering level may eliminate the possibility of legitimate e-mail being mistakenly put into your mtl-spam-filter folder, it may also increase the number of spam e-mails that end up in your INBOX.  No matter what you have your spam filtering level set to, it is recommended and encouraged that you make sure to check your mtl-spam-filter folder on a frequent basis, checking for any false positives (legitimate e-mail) that got filtered and deleting anything that you know is junk/spam. Please see the section below regarding automatic purging of e-mail from people's MTL spam filter folders.   If you are getting persistent false positives from a legitimate sender, please see the section below on blacklists/whitelists.

POP and MTL Spam Filtering

While the MTL spam filtering can be set up and will work, because of the use of POP instead of IMAP, you will have no way to view the contents of your mtl-spam-filter folder. This is very important since it is possible that some of your legitimate e-mail could be mistakenly put into the mtl-spam-filter folder and you will have no way of checking the contents of that folder. The easiest solution to this problem is to switch your mail client to use IMAP instead of POP and this is the recommended solution. If you would still like to continue to use POP, then please see the information below on spam headers and filtering using your e-mail client software and not the server side MTL spam filtering. If you have questions about this, then you should send an e-mail to mail-problems [at] mtl.mit.edu and someone will be able to answer your questions.

Automatic Purging of MTL Spam Folder Messages

Because MTL currently does not have any e-mail quota limits thus allowing users to store as much e-mail as they want on the MTL mail server, it is necessary to make sure that people's mtl-spam-filter folders do not grow without bound. In order to deal with this, messages older than 30 days will be automatically purged from all mtl-spam-filter folders.  Therefore, if you have MTL spam filtering enabled, it is recommended and encouraged that you make sure to check your mtl-spam-filter folder on a frequent basis, checking for any false positives (legitimate e-mail) that got filtered and deleting anything that you know is junk/spam.

Forwarding E-mail and MTL Spam Filtering

If you currently forward your e-mail from MTL to another address, then you cannot take advantage of the MTL spam filtering into the mtl-spam-filter folder.  However, you can still take advantage of the spam tagging that is taking place on every message that goes in and out of the MTL mail server. Please see the section below for more details on how to do this.

MTL Spam Header Information

If you would like to do your own filtering within each of your e-mail clients instead of using the automatic MTL server side filtering, then make sure to disable your MTL Spam Filter setting.  You will then need to set up your e-mail clients in order to do their own filtering. The specific header information you will need to search for within your e-mail client's filtering mechanism are the following:

MTL's Header Line: X-MTL-MailServer-SpamScore: ss....

where you choose the number of 's'es to filter on. The lower the number of 's'es, the more aggressive the spam filtering will be. For example, if you want to filter out all e-mail that gets a spam score of 6 or higher, then you should set up your e-mail client to filter out e-mail with the following line in its header information:

MTL's Header Line: X-MTL-MailServer-SpamScore: ssssss

Good Senders/Bad Senders

Good Sender lists (or whitelists) are lists of addresses that a user wants to receive e-mail regardless of whether or not it may be spam. Bad Sender lists (or blacklists) are lists of addresses that a user wants marked as spam regardless of whether or not it really is spam. You can now manage your MTL Good/Bad Sender lists on-line by going to MTL MUMMS and logging in. Once there you can click on 'View Your E-mail Settings' in order to view/change your current MTL e-mail settings including Good/Bad Sender lists. It is important to realize though that mail header information can be forged and it can be hard to tell where e-mail is coming from—thus blacklisting a certain e-mail address may not prove effective in stopping the spam since spammers can forge where their mail is coming from.

Message Scanning

All messages going through the MTL mail system are scanned. Messages that are found to contain computer viruses are not delivered and are quarantined. Other messages that contain possibly dangerous attachments/content are cleaned with said attachments/content being removed and replaced with an informative message regarding what was removed and why. The original unaltered message is then put into the quarantine area. The cleaned message is then delivered to the recipient while the sender also gets a message stating that the attachment/content was removed and why. The MTL mail server does a great number of checks on each message ensuring that potentially dangerous attachments/content are disarmed or removed and will not affect the user's client computer when reading their e-mail. Because of the number and variety of checks made and because spammers and virus senders are constantly changing their tactics thus necessitating changes on the MTL mail server, the specific checks that are done are not listed here. If you are having a particular problem with an e-mail message that you are trying to send or receive, please send an e-mail to mail-problems [at] mtl.mit.edu detailing the issues that you are having.

Attachment Blocking

Currently, the MTL mail server will block any attachment that contains a virus or is determined to be possibly dangerous content that should not be allowed into the user's e-mail program. If an attachment is found to contain a computer virus then its associated e-mail message is quarantined and is never delivered. If an attachment is found to contain potentially dangerous content then it is removed from the e-mail message but the rest of the message is delivered to the recipient along with a note stating that the attachment was removed and why. The sender also gets a message stating why the attachment was blocked from being delivered. For example, a reason for an attachment being blocked could be that it was an executable program (i.e. ends in .exe) and executables are not allowed.   The list of attachment types that are blocked continually changes so If you are having a particular problem with an attachment getting blocked, either one that you are trying to send or receive, then please send an e-mail to mail-problems [at] mtl.mit.edu detailing the issues that you are having.

Attachment E-mail Notifications

Currently, the MTL mail server will send an e-mail to both the sender and recipient if an e-mail attachment is found to have potentially dangerous content within it (as noted above, this does not occur when attachments are found to contain computer viruses). The recipient will get the original message with the attachment removed along with a note saying why it was removed. The sender will also get an e-mail message stating why the attachment was not delivered to the original recipient. This e-mail is done as an informational service in case the attachment was indeed legitimate and the sender needs to find another mechanism in order to send the attachment to the recipient. In most cases, these attachments, while not containing viruses, are bogus and there should be no need for the recipient to take any action. If you have any questions or problems regarding one of these e-mail notifications, then please send an e-mail to mail-problems [at] mtl.mit.edu detailing the issues that you are having.

HTML in E-mail

While HTML encoded messages are allowed, some particular HTML tags are not allowed due to their potentially dangerous nature and higher probability that they may cause harm on the user's client computer. If the MTL mail server finds these tags within a message, it will attempt to disarm them. This allows the message to continue to be sent to the recipient but with the dangerous tags being neutralized so that they do not cause problems on the user's client computer. If you have any questions or problems regarding HTML encoded e-mail that you are receiving, then please send an e-mail to mail-problems [at] mtl.mit.edu detailing the issues that you are having.

Phishing Scams

A common attack by spammers and hackers is to send fraudulent e-mails that appear to be from legitimate companies. They do this in order to try and get you to click on URL links embedded in the mail so you can either give them personal information such as a credit card number or they can try and install malware on your computer without you knowing it.  In order to lessen the risk of such phishing e-mails, MTL will alert users to possible phishing scams/attacks within e-mails. While the URL link will not be disabled, you will see a notice stating that this could be a phishing fraud/scam. If you have any questions or problems regarding phishing scam e-mails that you are receiving or legitimate e-mails being tagged, then please send an e-mail to mail-problems [at] mtl.mit.edu detailing the issues that you are having.

Mailing Lists

MTL maintains various system wide mailing lists for the MTL user community such as MTL All, CAD Users, and FAB Users.  In addition, MTL supports and maintains various research group mailing lists as well as other MTL CAD & IT and administrative mailing lists.

Requesting a New MTL Mailing List

To request a new MTL mailing list, please send a message to problems [at] mtl.mit.edu with the following information:

  • The e-mail name of the mailing list (e.g. <your mailing list name>@mtl.mit.edu)
  • The list of e-mail addresses that should be initially on the mailing list.
  • The owner of the mailing list (i.e. who will be the person to edit and maintain the list)

Maintaining a MTL Mailing List

If you are the owner of a MTL mailing list and you wish to edit/change the list of e-mail addresses that are on this list, then you should go to the main Mailman web page for the list that is of the form:

https://mtl.mit.edu/mailman/admin.cgi/<your_list_name>

where <your_list_name> is replaced with the actual name of the list.

If this does not work or the page does not exist, then please send a message to problems [at] mtl.mit.edu with the following information:

  • The e-mail name of the mailing list (e.g. <your mailing list name>@mtl.mit.edu)
  • What it is that you want done to the list (e.g. adding/removing member, etc.)

Removal from a MTL Mailing List

If you would like to be removed from a MTL Mailing List, then please go to:

https://mtl.mit.edu/mailman/listinfo.cgi/<your_list_name>

where <your_list_name> is replaced with the actual name of the list

Scroll to the bottom of the page where you can choose to unsubscribe from the list.

If this does not work or the page does not exist, then please send a message to problems [at] mtl.mit.edu with the following information:

  • The e-mail name of the mailing list (e.g. <your mailing list name>@mtl.mit.edu)
  • Your e-mail address or username that should be removed from this list.

Vacation Configuration

Enabling an autoreply or vacation message allows the user to set up an automatic message in response to incoming e-mail. Normally this would be done when one is away on vacation or cannot access/read their e-mail for an extended time.  In addition to sending an autoreply, a copy of the message will be stored in the user's local mailbox to be read when the user returns. Finally, vacation keeps track of whom it has replied to and will only send a single auto-reply once a week to each recipient.

You can now change your MTL Autoreply settings on-line by going to MTL MUMMS and logging in. Once there you can click on 'View Your E-mail Settings' in order to view/change your current MTL e-mail settings.