How to Configure Real Time Blacklists for Microsoft Exchange 2000 and 2003

Products

• Mail Security for Microsoft Exchange

Issue/Introduction

You have Symantec Mail Security for Microsoft Exchange. You want to use a Real-time Blacklist (RBL), also known as a DNS-based Blackhole List (DNSBL), to screen email senders. You need instructions to configure this feature

 

Resolution

To configure message rejection with an RBL

1. In the Symantec Mail Security for Microsoft Exchange interface, on the primary navigation bar, click Policies.
2. On the sidebar, under Antispam, click Blacklist and Whitelist.
3. In the text box under Real-time Blacklist, type the domain name of your RBL provider.
   You can add more than one RBL provider. To add additional providers, type all of the provider domain names, one per line.
4. Click Deploy Changes/Deploy all.

Symantec Mail Security for Microsoft Exchange is now configured to use the RBLs that you specified.

You can generate a summary report to track the RBL checks and email rejections.


 

Technical Information
How to locate RBL (DNSBL) providers

Use any search engine to search for "DNSBL Providers", and you should see a list of blacklist providers. The following are a few examples of DNSBL providers:

• cbl.abuseat.org
• www.spamhaus.org
• spamcop.net

How to specify a Real-time Blacklist
You must specify the domain names of DNS-based antispam services to use. Populate the Real-time Blacklist domain name field with the RBL service that you plan to use.

What happens to rejected messages?
If an RBL check matches the IP address of the connecting email server, and the sender or recipient of the email are not in the whitelist, the connection is terminated before the DATA command. The server that initiated the connection receives an SMTP 550 error, which indicates a permanent failure.

The message looks like the following:

"550 5.2.1 Mail from 192.168.247.134 refused: spam site."