Tech Support

Internet Exchange Frequently Asked Questions

Internet Exchange Messaging Server
Anti-Spam Module FAQ

Introduction
The Internet Exchange Messaging Server Anti-Spam Module (both Enterprise and Workgroup versions) is a stand-alone unit that provides the system administrator with options to create a list of unwelcome IP addresses/address ranges or a list of banned addresses/address ranges using simple Graphical User Interfaces (GUI's).   It is also capable of verifying the corresponding name of an IP address during the initial stage of the SMTP session via reverse DNS lookup to filter out forged names, thereby blocking out potential spammers even before they can enter the system. 

In addition, the Anti-spam Module features Real-time Blackhole Lists (RBL) support.   An RBL is a blacklist of IP addresses that have been confirmed to send spam mail, be friendly to spammers, and/or totally open to mail relaying.    It makes use of the Domain Name System (DNS) to distribute databases of blacklisted IP addresses.   Internet Exchange Messaging Servers support an arbitrary number of RBL-style systems, though at present if enabled, the following five RBL style systems can be easily configured:

• MAPS-RBL (Mail Abuse Prevention System's Real-time Blackhole List)

• ORBS (Open Relay Behavior-modification System)

• MAPS-DUL (Mail Abuse Prevention System's Dial-up User List)

• Internet Mail Relay Services Survey (IMRSS)

• DynamicIP Spam Sources List

MAPS-RBL is a system that creates intentional network outages so that the transport of unwanted mass email is prevented.  ORBS is a database that lists SMTP servers that have been confirmed to permit third-party relay.  MAPS-DUL, on the other hand, lists dial-up and other dynamically assigned IP addresses to prevent trespassing by people and/or organizations who sent unsolicited email using direct connections to their victims' mail server without using their ISP's mail server as a relay or gateway.

Additional Documentation
Additional Anti-Spam related information can be found in the following documents

• Anti-Spam Module Data Sheet

• The Internet Exchange 4.0 Anti-Spam Module Now Supports Global Real-time Spam Database Reference

• Enhancing The Anti-Spam Capability of the Internet Exchange Messaging Server by Activating RBL Support

• The Internet Exchange Messaging Server Preprocessor: A Sure-Fire Protection Against Computer Viruses and Junk Spam Mail

• System Level Spam Blocking via Internet Exchange Messaging Server's Anti-Spam Module, @Internet Exchange: Internet Exchange News, March 2001