>>It does require SMTP server.
>>
>
>I don't think so - it talks directly to the smtp of the addressee. One might say that this is also an smtp server
>
>What I mean is that you do not need to talk to your smtp server

You're wrong. You either have to specify SMTP server in smtp_host property or the class will look in the registry for it and generate an error if it cannot find SMTP server.