How to Manually Create an RBL Block

How can I manually create an RBL block, so that my system will block it before it receives the full message?

If you need to block a specific IP address at the SMTP level, do the following:

An example of when you might need to do this is when a certain Sender keeps sending a large file.

1) Connection Drop needs to be enabled.
2) Edit the 'hosts' file. Located in sys:/etc on Netware and /etc/ on Linux
3) Make an entry in hosts file for the IP address you are trying to block. The IP address will need be in reverse order with the RBL server that you are using. For example:

127.0.0.4       41.24.1.198.bl.spamcop.net

The actual IP address that will be blocked is 198.1.24.41. In order for this to work you need to have bl.spamcop.net listed among your RBL servers and the IP address in reverse order as shown.

After changing the hosts file on Netware you will need to run 'reinitialize system' for it to see the new entry. The change on Linux is immediate.

The next time an email comes in from that IP address, it will get dropped for RBL at the SMTP level, preventing your system from accepting the email.

This article was originally published in the GWAVA knowledgebase as article ID 1299.