Using Real-time Blackhole Lists for spam filtering in F-Secure
Note: This article applies to customers using F-Secure Internet Gatekeeper (IGK) versions 4 and 5. If you are using spam filtering and have enabled the Real-time Black List (RBL) feature, read this article carefully.
Real-time Black Lists (RBL's) are used to publish the addresses of computers or networks that are linked to spamming. When this setting is on, the spam filtering uses RBL's to detect spam messages. An email is detected as spam if the source IP address (when using SMTP) or IP addresses in the received headers field are registered in an RBL server.
Currently, in a newly installed IGK, RBL spam scanning is off. The RBL services are provided by the following third-party vendors by default: Spamhaus and SpamCop. The user can add or remove these services if desired. However, before taking an RBL server into use, the respective usage terms should be read and accepted. This is also required for the following default servers that have been in use up to IGK version 5.22:
Currently, Spamhaus offers two usage models: Free Use and Professional Use where the latter is a commercial service. Corporate customers need to evaluate the usage terms carefully and decide whether they qualify for free use or not. SpamCop is essentially free to use.
In our future releases of IGK, we will remove these default values and document them in the Admin Guide as suggestions.