The Postfix online documentation describes configuring Postfix for delivery to a FAX system and setting up a gateway for UUCP. These provide good examples for configuring Postfix to work with all kinds of special devices. If you need to create a gateway between different types of systems or different networks, transport maps provide the mechanism for directing mail to the other systems or devices.
Introduction
Prerequisites
Postfix Architecture
General Configuration and Administration
Queue Management
Email and DNS
Local Delivery and POP/IMAP
Hosting Multiple Domains
Mail Relaying
Mailing Lists
Blocking Unsolicited Bulk Email
SASL Authentication
Transport Layer Security
Content Filtering
External Databases
Appendix A. Configuration Parameters
Appendix B. Postfix Commands
Appendix C. Compiling and Installing Postfix
Appendix D. Frequently Asked Questions