question about smtp service

External Since: Feb 24, 2008 Posts: 1

I'd like to know if it is possible using any e-mail address as sender, even
a non-real one. I'd like users of my web site write me only by form on my
site, so I'd want to use a non-real address to answer them.
Is there any check on e-mail address used as sender?

External Since: Feb 26, 2008 Posts: 7

If you are using an SMTP server run by an Internet Service Provider,
then they can implement a security layer that allows only their valid
customers to send email through their server.

If you are hosting your own SMTP server, which is then uploading
traffic onto the internet through your Internet Service Provider, then
you can use any email address as long as it has a valid form in the
email's header. In this case, it doesn't matter if the sender email
address actually exists.