[HECnet] TOPS-20 outgoing mail relay config

[Mark Abene]

Long story short: after moving to the other side of the country a year
ago, I finally (recently) had time to get my TOPS-20 system (KLH10)
back up and on HECnet.   Only to discover that Comcast (cablemodem
service), in their wisdom, blocks port 25 in and out, in an effort to
"combat spammers".
This rather complicates my e-mail setup in TOPS-20.   For incoming, I
simply created a transport relay on an external mail server that I
control in order to deliver mail on an alternate port number that
isn't blocked, and then simply port forward it from my firewall to tcp
port 25 on the TOPS-20 server.   That was the easy part.   Outgoing mail
from TOPS-20 is proving to be a bit more difficult.   I was thinking I
may be able to intercept all outgoing traffic from TOPS-20 bound for
port 25 at whatever smtp server, and redirect it to a single smart
host (mail server on the net which I control), on an alternate port
that isn't blocked.   Might work.
The reason I'm asking about this here, is I'm curious given the mail
transports at LEGATO and CHIMPY on HECnet, if anyone has tried simply
setting one of them up as a "smarthost" relay for all outgoing mail in
TOPS-20, perhaps via the <mail>mailer-relay-info.txt config file.
Unfortunately the syntax of mailer-relay-info.txt is a little
confusing; despite the explanation in the file's comments, there are
no clear examples, and trying to follow the logic of the options in
the MMAILR MACRO assembly code is less than helpful in modern mail
server context (transmogrify?? who's domain??).
Any suggestions welcome.

-Mark