Help Fight Spam in Exchange 2003
June 19, 2008 · Print This Article
Spam is a difficult animal to tame, so any product that can help fight it will certainly be regarded by network admins, even more so if it is FREE!
In Exchange service pack two Microsoft integrated an Intelligent Message Filter or IMF. You can use IMF and IMF tools to set thresholds on SPAM Emails. IMF also includes a builtin way to dynamically check Realtime Block Lists (RBL’s). RBL’s are pretty self-explainatory, they are dynamically updated lists that provide domain names and IP addresses of SPAMing sources. Two organizations that are known for keeping great RBL’s are spamcop.net and spamhaus.org. Both of these site even provide up-to-date stats on the world of SPAMing.
In order to use RBL’s from spamcop and spamhaus, follow these steps:
1. Go into your Exchange 2003 System Manager.
2. Go to the Global Settings -> Message Delivery
3. Right click on Message Delivery and select “Properties” from the drop down menu
4. Go to the “Connection Filtering” tab.
5. Click on the “Add” button.
6. For “Display Name” you can add whatever you like, but usually the name of the RBL server is what you want to put in there.
7. For “DNS Suffix of Provider” you will want to put the url to the server - for example the one for Spamhaus is zen.spamhaus.org
8. If you think you want a custom error message, then fill out that field with whatever you want it to be.
9. Finally click OK and the RBL will be assigned to IMF.
As you can see on that main screen there is the ability to have a global accept and deny list with IP addresses, as well as an exception list - this is where you can whitelist/blacklist people in if you like.
After you are done adding your RBLs, click on OK for the main menu and then you will likely get a popup reminding you that you need to activate these rules.
Just like that popup says, you need to activate them - so if this is your first time setting up a connection filter, then go into the System Manager -> Administrative Groups -> and then to the server that you want to activate this on.
Once in the section for your server, then go to Protocols -> SMTP -> Default SMTP Virtual Sever and then right click on that and select “Properties” from the menu that comes up.
1. Under the General tab, click on “Advanced”.
2. Select the port 25 identity and click on the “Edit” button.
3. Check the “Apply Connection Filter” and then select OK all the way out until you are back at the System Manager.
4. Watch you SPAM messages typically get cut in half!
The two filter manager URL’s we used are as follows:
Spamhaus: zen.spamhaus.org
SpamCop: bl.spamcop.net
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