Postfix Email Server

Installation
TODO

Tweaks

 * Backscatter Rejection
 * Greylisting
 * Postfix Relay

Log files
/var/log/mail.info mail
 * If problems, the places to look for useful info are:

Postfix queue control
Sometimes you may need to check what's in the queue of emails waiting to be fully processed. service postfix stop mailq | less postqueue -p | less     # it's the same postcat -vq ID | less postsuper -d ID
 * Optional: stop Postfix, in case you need to investigate something and stop incoming/outgoing activity.
 * print a list of all queued email:
 * print a specific email by its ID
 * delete a specific email by its ID