One of the reasons why people just go "meh, whatever, good enough" and install wordpress, use some popular wordpress contact form. Have it give mail to a postfix daemon on same server that listens only on localhost and relays outbound via your own infra. Or similar. A base wordpress install is pretty hard to screw up if you don't start adding weird plugins to it, and it will auto-update itself by default. I can't even imagine taking the time now to do this by hand.