Re: what do I need smtp server for?
If you're running your own server from home, the only ports that you should open are the ones that you are actually using: http,https,control panel.
You shouldn't ever close the smtp port because then no one on your network will be able to send mail. Just because something is there, that doesn't mean you have to actually use it. You don't need it, just let it be.
"Design is not just what it looks like and feels like. Design is how it works. "-Steve Jobs