Hi, I found some interesting filtering recipes maintained in Postfix format, such as http://www.hardwarefreak.com/fqrdns.pcre.txt
Since I'm not running Postfix, I think I need to roll my own filter in order to run those recipes. At a first glance, smtpd_check.c and dict_pcre.c look like good starting points. However, it is not clear to me how/if modifications are allowed: The derivative work I'd do doesn't seem to be a "Contribution" in the sense of the definition given in LICENSE, as it is not going to be added to, nor distributed along with Postfix. In addition, PCRE is mentioned in HISTORY in 1999, which is the last date in the copyright notice imposed by LICENCE for contributions. In fact, only the first of those two C sources says "The Secure Mailer license must be distributed with this software". And, except strcasecmp.c, no C source contains any copyright notice. GNU just say that "IBM Public License, Version 1.0 [...] is a free software license. Unfortunately, it has a choice of law clause which makes it incompatible with the GNU GPL."[1] IANAL, but the latter sentence would seem to refer to the last paragraph of the Secure Mailer license. [1] https://www.gnu.org/licenses/license-list.html#IBMPL The software I'd target, Courier-MTA, is GPL-licensed. Some parts of the filtering interface I use were derived from it. May a mix those sources? If Wietse writes a somewhat affirmative reply, I'll file it along with both licenses, and let any idle lawyer loiter over that at will. Ale
