I currently work for a bank, so security is paramount.
I'm trying to secure outgoing email from our fax machines to our email host, rackspace. On a normal client, I would simply turn on ssl, and everything is fine. However, our fax machines do not support ssl. How would I go about encrypting the normal smtp traffic so that it is using ssl before it leaves my network? Could I use postfix on a server somehow? maybe stunnel?
I attached a simple network diagram of what I'm trying to do.