RRDtool is available under the terms of the GNU General Public License. This means you can do most things you want with this software as long as you do not claim you created the software and don't sell it (or modified version of it) under a license other than the GNU GPL.

One of the things I get out of RRDtool is 'Being Known in the Industry'. This only works if you give credit to RRDtool. This means that you mention RRDtool on webpages and other publications containing graphs created with RRDtool. If possible, a link should be included in the publication, pointing to the RRDtool homepage. Best is to include the RRD TOOL logo on these pages.

I am giving RRDtool away for free. This does not mean, that I don't like getting appreciation for my program. If you like RRDtool and want to show me your appreciation, have a look at my CD wishlist . Please put your eMail address into the the Message area, so that I can thank you for your present. I do keep a list of People who sent me CDs. You can look at it here.

remember, information is not knowledge, knowledge is not wisdom wisdom is not truth truth is not beauty beauty is not love love is not music music is the best -- frank zappa