Mailfilter FreeBSD Jail

Background

FreeBSD's jail(8) has some extraordinary side-effects when used in conjunction with
postfix as a mailserver. It gives you the ability to run many mailservers that are
logically separated on the same machine, in fact sharing resources like OpenBSD's spamd
and even the underlying software (including postfix, amavisd-new, etc). You can also
set this up in such a fashion as to keep separate config files for each jail. That is
the way that will be documented here.

Requirements

• FreeBSD (recommended: 6.2-RELEASE or newer)
• a full /usr/src and /usr/obj tree built already with whatever custom options in make.conf
• enough disk space for multiple installs of the OS to co-exist on the same partition(s)
• enough RAM to delegate to many running instances of child software.
• postfix (recommended: 2.3.5 or newer) (/usr/ports/mail/postfix)
• amavisd-new (recommended: 2.4.4 or newer) (/usr/ports/security/amavisd-new)
• ClamAV (recommended: 0.90 or newer) (/usr/ports/security/clamav)
• SpamAssassin (recommended: 3.1.7 or newer) (/usr/ports/mail/p5-Mail-SpamAssassin)
• And, of course.. the dependencies of all the above-mentioned software.