Use the following information to decide whether you want every sent email from every employee to carry a company disclaimer message:
If you do decide in favor of email disclaimers, be aware that there is no way to fully implement them at the server level.
- The only proper way to do disclaimers is to have a policy requiring users to insert them in their mail clients.
- The next best approach is to write a conversion channel to add the disclaimer.
The conversion channel can be used to perform arbitrary processing on each message on a per-body-part basis. In this case, you want the processing to be that of appending a disclaimer. Modify the MTA configuration files so that all your mail passes through this conversion channel. At a minimum, construct one conversion to account for text/plain message body and one to account for HTML. Add more conversions if the actual messages being sent have some other sort of MIME structure unique to your deployment.
For more information, see Using Predefined Channels#The Conversion Channel.
If you configure the MTA as previously described, and run into problems where the disclaimer is not appearing, begin by looking at your conversions file, and get a master_debug conversion channel debug log file. The tcp_local_slave.log-* file, and the mappings file, provide information about getting the message to the conversion channel. The appending of the disclaimer would be done by the conversion channel, so you need to see what the conversion channel itself is doing.