_ehlo example

// Validate client hostname         if (!$this->_validHost->isValid($host)) {
            /** * @see Zend_Mail_Protocol_Exception */
            throw new Zend_Mail_Protocol_Exception(join(', ', $this->_validHost->getMessages()));
        }

        // Initiate helo sequence         $this->_expect(220, 300); // Timeout set for 5 minutes as per RFC 2821 4.5.3.2         $this->_ehlo($host);

        // If a TLS session is required, commence negotiation         if ($this->_secure == 'tls') {
            $this->_send('STARTTLS');
            $this->_expect(220, 180);
            if (!stream_socket_enable_crypto($this->_socket, true, $this->getCryptoMethod())) {
                /** * @see Zend_Mail_Protocol_Exception */
                throw new Zend_Mail_Protocol_Exception('Unable to connect via TLS');
            }