Used to identify the sending server to the receiving server.
This makes sure that client and server are in a known state.
Implements RFC 821: HELO
and RFC 2821 EHLO.
public function hello($host = '')
{
//Try extended hello first (RFC 2821)
return (bool) ($this->sendHello('EHLO', $host) or $this->sendHello('HELO', $host));
}