public function set_hostname($hostname, $port_number = null)
	{
		if ($this->override_hostname)
		{
			$this->hostname = $hostname;

			if ($port_number)
			{
				$this->port_number = $port_number;
				$this->hostname .= ':' . (string) $this->port_number;
			}
		}

		return $this;
	}