Is it safe to use the public IP of a server as a relay in IIS? I'm
testing the SMTP server in IIS. A web app on this server needs to be
able to send email. The only way I've got it to work so far is by
going into Default SMTP Virtual Server Properties > Relay Restrictions
> selecting "Only the list below" and adding the public IP with access of "Granted."

Is this safe? Or is this something that can easily be exploited? I
would think if it's only accepting relays that come from it's own IP,
this would work out, but I'm not sure.