Hi, and welcome to LQ. You can probably find the answer to your question in the Rute book (http://rute.2038bug.com/index.html.gz
). Look at sections 9.3 and 9.4.
Oftentimes in this forum you will get directed to reading material instead of getting an answer directly. This is to get you in the habit of using the printed documentation. Or sometimes you will be told to use Google. Admittedly, much of the existing documentation on the web is outdated, or confusing to those who are new. So don't hesitate to ask here, but be prepared to take some flak when some of the members get on your case for not making an attempt to do a search first.