ipfilter on GNU/Linux: Is It Finally Here? (Linux Journal)

Posted May 28, 2004 19:17 UTC (Fri) by andre (guest, #11559) [Link]

which by the way is far better than ipfilter.

Posted May 30, 2004 1:04 UTC (Sun) by bignose (subscriber, #40) [Link]

Specifically, the license granted on the code did not allow redistribution of modified or derivative works (and the author "clarified" this explicitly, during the break with OpenBSD), and thus was not a free software license.

Posted May 30, 2004 1:29 UTC (Sun) by bignose (subscriber, #40) [Link]

While OpenBSD did remove the IPF code because the license was at that time non-free, the author appears to have updated the license in the interim. (OpenBSD still does not include IPF, and with PF working quite well, it likely will not do so in the future.)

The current IPF code (linked from the article) has a license that appears to this reader to be free software; specifically, the IPFILTER.LICENSE file says:

 * Redistribution and use, with or without modification, in source and binary
 * forms, are permitted provided that this notice is preserved in its entirety
 * and due credit is given to the original author and the contributors.
 *
 * The licence and distribution terms for any publically available version or
 * derivative of this code cannot be changed. i.e. this code cannot simply be
 * copied, in part or in whole, and put under another distribution licence
 * [including the GNU Public Licence.]

The author seems to dislike the BSD license loophole (where the code can be redistributed under a different license), and has an unexplained hatred for the GNU licenses, even naming a non-existent license (the "GNU Public License"); but all these clauses appear to be free.