Very very aware.

So you had another mail server elsewhere that port forwarded port 25 via port 22 to your internal mail server’s port 25.

I take it that outside mail server was secure.

That’s an impressive setup.

Did you really only use it when you were home? If you used it outside the firewall then port 25 must have been open also.

I used to run my own server and this was in the early 90s. Then one day, perusing the logs I realized I was not smart enough on the security front to even attempt such a thing. It was quickly shut down and the MX record moved to an outsourced mail provider.