🚀 go-pugleaf

About a week ago, I posted a query about sendmail and the
possibility of using SMTP through a serial line.  The
results of that query weren't encouraging, so I'd like
to describe our situation in more detail and solicit
suggestions.

Basically, we have been given the task of providing
straightforward (preferably "transparent") file transfer
and electronic mail between 4.*bsd and a VMS system.
The best way to do this, of course, would be to procure
TCP/IP support for VMS and connect the systems in a local
network.  Unfortunately, we cannot be certain that
the machines can be connected in this way--they might
even be miles apart, connected by modem.  So we need
transfer mechanisms that (a) are cheap to set up (we don't
have the manpower to write this stuff completely from
scratch) (b) can operate through a (possibly unreliable?)
serial line, and (c) can be made to interact smoothly
with existing mail tools on both ends.

We are, for example, considering Kermit as the basic mechanism
for file transfer, because it operates on many systems, and
because it's basically a freebie.  We anticipate setting up
a quasi-batch kermit-copy command at the Unix end which would
work similarly to UUCP.   However, Kermit isn't particularly
good as a mail delivery system.  To transfer mail from Unix to
VMS via Kermit, the mail deliverer would ask Kermit to transfer
the message (with envelope) into a well-known mail spooling directory
on the other side, from which a daemon would periodically retrieve
messages and deliver them into the local mail system.  This seems
rather clumsy.

SMTP seems like a nice simple protocol for serial lines, but it
really was designed on the assumption of a reliable virtual circuit.
Serial lines (especially via modem) aren't really reliable enough to
use with SMTP without some kind of error-correcting protocol being
layered into the line driver somehow.  Further, Sendmail only runs
an SMTP server via a serial line (via the -bs flag); since it doesn't
implement TURN, it's not usable for bidirectional mail transfer via
a serial line without extension.

There appear to be serial-line IP drivers available for Unix; I don't
know what the licensing arrangement is, nor do I know if something
analogous exists for VMS.  Evidentlyl, SMTP could be used in both directions
through such an arrangement (albeit slowly).

Is there a UUCP for VMS?  How much does it cost?

Does anyone have any further ideas?