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Filtering Out Spam at UIC
0. Contents 1. Canned Spam Filter 2. Upcoming Changes to Spam Filtering 3. Anti-Spam Filter FAQ

Upcoming Changes to Spam Filtering

 

Introduction

On Tuesday morning, November 9th, 2010, the ACCC began phasing in new Barracuda brand Anti-Spam appliances for our incoming email sent to uic.edu.

Our tests indicate that this new system will greatly improve our spam and virus filtering. The switchover, however, will be gradual and closely scrutinized, in order to prevent any email delays or other complications. We welcome any feedback, good or bad; send it to spamfiltering@uic.edu. If you are experiencing trouble of any sort with the new system, please include as many details as possible.

 
     
 
     
Specific changes
 

Most email users will not notice any difference difference, other than better spam and virus detection. But there will be a few differences from our previous setup that may affect a small number of users who have specialized configurations on their email programs or on the servers that they have their @uic.edu email forwarded to. These changes are the following:

  • Subject header

    Previously we allowed you disable the ***SPAM*** subject line tag on mail detected as spam. In our new implementation, however, that can not be disabled for individual users, so it will appear on all spam messages.

  • Header Filtering

    If you use local filters on your email client to filter out spam based on the special headers the ACCC has been adding to messages tagged as spam, you will need to adjust your local filters. Previously, you could filter out spam based on a X-UICClass: header, but that header will disappear as the transition progresses. To catch all spam from either system, your filter could look for both X-Spam-Status: Yes (to catch spam from our old system) and X-Barracuda-Spam-Status: Yes (to catch spam from our new system).

  • Whitelist

    Your "whitelist" is still managed via the ACCC's anti-spam Web utility, but it no longer allows "wildcards" in your entries. Now you must specify a complete email address (such as grandma@aol.com), or a complete domain name (such as aol.com).

    Existing entries that do not follow these rules will not work on the new system.

  • Preference update delay

    For the moment, any changes you make to your preferences will not be immediately reflected in the Barracuda system. It may take up to an hour for changes to take effect. This will be remedied once the switchover is complete.

  • Depreciated options

    Because the new Barracuda system implements features differently than our current system, some options available on the ACCC anti-spam web utility will no longer be applicable. These are the following:

    • foreign language character sets
    • greylisting, and
    • message modification (optionally converting spam messages into an attachments)
  • IP Addresses

    While our current system uses the sending IP address to filter spam to some degree, the new Barracuda system depends heavily on this: the IP address's reputation. Many locations have Barracuda systems deployed. These Barracudas communicate with each another about spam sources and use that information to modify filters across the Barracuda network.

    This works quite well most of the time, but now and then a home user on Comcast, AT&T, or so on, will randomly pick up an IP address that has a bad reputation when they reset their home routers. Maybe a neighbor's PC was compromised and sent out spam. Later, the neighbor's router releases the "bad" dynamic IP address and your router picks it up. In this case, mail sent from your PC to UIC will be rejected back to the sender with an explanatory message containing "bad reputation". If this happens to you, you should reset your own router again (perhaps repeatedly) until you can send mail to UIC again.

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    Other items
     

    As our phase-in of our Barracudas continues, other noteworthy items will be listed here. If you run into problems that you believe are related to the Barracuda phase-in that are not listed here, please send a detailed problem description to spamfiltering@uic.edu and we'll look into it.

    Thanks.

     
    Filtering Out Spam at UIC Previous:  1. Canned Spam Filter Next:  3. Anti-Spam Filter FAQ


    2011-2-22  systems@uic.edu
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