Every now and then I install a fresh install of Linux Mint, I always forget at least one program or utility. And that tends to be an smtp server. I’ve used Postfix in the past, but I find sSMTP to be a lot easier, and less resource intensive.
I use GMail, both for incoming and outgoing email. I can never remember exactly how to configure sSMTP to work with GMail. Fortunately, Mark Sanborn did it for me!