Chainmail is intended to be a sendmail replacement for workstations. It is written in perl.

Included are an RFC 822 parser (the most complete perl implementation AFAIK), a mail queuing system, an ESMTP client and Net::DNS by Michael Fuhr.

At the moment, there are only per-user mail queues. In the future, chainmail should be made trustworthy enough to be setgid mail and deliver messages to a central shared queue. At the moment the problem with this is that a cunningly created queue file could quite possibly make chainmail eat CPU forever. In other words, chainmail has not been audited for denial of service or other security vulnerabilities, so it should not be run by (for example) a cron script or with elevated privileges.