Use ASSP to Prevent Spam
From Daily Data
Contents |
Spam Filtering
Daily Data has implemented a new spam filter for commercial domains hosted with us. The following article is designed to help the e-mail clients involved with the new service.
We have implemented the Anti-Spam-SMTP-Proxy (ASSP) from http://assp.sourceforge.net/ for this purpose. If you simply want to know how to use the new system, the section Quick Instructions is sufficient. The following articles are for those of you wanting more details.
Quick Instructions
In the following, we use the term @mydomain.com to indicate you are to put your domain in this location. For example, if your e-mail address were suzy@example.com, example.com is your domain. Thus, when we say you should send a message to ThisIsSpam@mydomain.com, you would replace mydomain.com with your domain, example.com and send the e-mail to ThisIsSpam@example.com.
- The first thing you should do is verify that all of your regular correspondents are not spammers:
- Create a new e-mail message
- In the To field, enter AddToWhitelist@mydomain.com
- In the BCC field, add everyone in your address book
- Send the e-mail
- You may do this at any point in time in the future, but anyone you send an e-mail to is automatically added to the whitelist.
- If you get spam in your mailbox, choose "Forward as an Attachment" and send the e-mail to ThisIsSpam@mydomain.com.
- If you receive a message that is not spam, but is marked as spam, choose "Forward as an Attachment" and send the e-mail to NotSpam@mydomain.com
- For a quick tutorial, send a blank email to spamhelp@mydomain.com.
Details
How it Works
ASSP is a program which uses a 'smart' filter which can predict with great accuracy which pieces of incoming mail are spam and which are not. This is automatically applied by Daily Data's mailserver and prevents all obvious spam from even being accepted into your mailbox.
ASSP uses Bayesian filtering, an advanced filtration system which can 'learn' over time to more accurately predict spam. As the filter becomes more accurate, fewer pieces of spam will arrive in your account.
Training the Server to recognize Spam
ASSP's filter is a 'smart' filter. It learns from what items you mark as spam or not spam. Items that it already knows are spam are not even accepted to appear in your mailbox. In the event that you receive a spam email, simply forward it to the address 'thisisspam@mydomain.com'. This will help "teach" the spam filter to recognize similar e-mail as being spam in the future.
Training the Server to learn when something is not spam
If ASSP is unsure if an item is spam, it will allow it to be sent to you, marked with a [spam] header. If these items are spam, simple forward them (as above) to 'thisisspam@mydomain.com'. If they are NOT spam, forward them to 'notspam@mydomain.com'. Providing this feedback to the ASSP filter will allow it to better make decisions about what is or is not spam in the future.
Whitelisting
A whitelist is a list maintained by the server of email addresses you have designated as safe and not spam. While it is possible to whitelist any email, it's frequently used for emails from commercial websites which you HAVE subscribed to (i.e. Amazon.com or Ebay newsletters, daily news filters from CNN.com, or other mass-mailed messages which you DO want to make sure you read.)
Because spammers will frequently fake email headers in order to make spam appear as if it comes from a sender you know, whitelisting should be used sparingly.
In order to list an email as safe and have it added to the whitelist, forward a message from that email to 'addtowhitelist@mydomain.com'. If you wish to remove a name from the whitelist, forward an email from that address to 'removefromwhitelist@mydomain.com'.
A white list is sometimes referred to (for example, in hotmail accounts or on Y!Mail) as a 'safe list'.
Adding your address book
When you first set up your account, you will likely have a list of e-mail accounts in your address book containing people you commonly correspond with. If you add these addresses to the whitelist, you should send an e-mail to addToWhiteList@mydomain.com containing all of the addresses. The addresses can be anyplace in the message: you can BCC the addresses, or simply include them in the body of the e-mail. Under recent versions of Thunderbird, there is a very simple procedure for doing this. If you are able to export your address book to a text file, you can simply open the text file with an editor, copy the contents, then paste them into the message.
You will get a response stating that all the addresses have been added to the whitelist.
Thunderbird
- Create a new e-mail
- In the To: section, put addToWhitelist@mydomain.com
- Put in a subject (it does not matter what)
- Put your cursor in the Body of the e-mail
- Open the Address Book by selecting Tools | Address Book
- Move the Address Book window so you can see part of the body of the e-mail
- Select the first entry in the address book
- Press ctrl-a to select all entries
- With the left mouse button, drag the list to the body of the e-mail message
- Close the address book
- Send the e-mail.
Outlook
Unfortunately, we have not come up with a simple way of doing this under Outlook. To perform the same action from Outlook, you must manually select each message and set it as a BCC (Blind Carbon Copy). The message will not be sent to them (it is intercepted by the AddToWhiteList function), but all the addresses in your BCC will be whitelisted.
Find Missing e-mail
Sometimes, the server will incorrectly mark a message as spam. When the server determines a message is spam, it sends it to the special mailbox 'spam@mydomain.com', which your systems administrator has access to (it is possible the administrator has opened this account to everyone). In some cases, your administrator has requested we set up individual spam accounts, in which case it will be your e-mail address, with -spam inserted right before the @ sign, i.e. rod-spam@dailydata.net.
You can log into the spam account and transfer the e-mail to your account, by simply forwarding it to your e-mail account. More importantly, you should forward the e-mail As An Attachment to 'notspam@mydomain.com'. This will help the system to learn the message is not spam, and will also add all e-mail addresses to the whitelist.
