Nevertheless, Rosen, on behalf of open-source developers, has been trying to get Microsoft to back down on these sticking points. "For the last few weeks I have been quietly negotiating changes to the Microsoft Sender ID Patent License Agreement with the responsible attorney at Microsoft. I have kept Eben [Moglen, the FSFs general counsel] and several members of the IETF working group fully informed as those discussions proceeded. It has been a difficult chore because Microsoft objects to several of the important changes I asked for that could transform this into an open-source-compatible patent license," he said."The absence of sublicensing is but one of the important concerns Ive raised with them. There are other parts of this agreement that would make it unacceptable if it were part of an open-source license although, in fairness, I should say that it is a far better license than Microsoft has ever offered before."Microsoft has made some changes to its license as per Rosens and other open-source advocates suggestions, but on the major issue of sublicensing, the company has remained firm. That said, Microsoft might be willing to compromise on this issue in future versions of the license, according to Microsoft sources. Microsoft badly wants its patent accepted as part of an IETF standard. To do that, it may be necessary to compromise on the sublicensing issue. Click here to find out why Security Center Editor Larry Seltzer thinks Microsoft should put up or shut up on this issue. Eric Allman, chief technology officer for Sendmail Inc., a leading mail server company, said, "In our discussions with Microsoft we were able to get them to make some improvements, at least to the point of making it clear that end users didnt have to execute a license with Microsoft." Allman added, "The fact that redistributors still do is a problem, and will probably prevent us from bundling Sender ID with Sendmail." As a result, Jennings noted, "if people implement Sender ID with the license as it stands, there will be an unreasonable amount of friction. It will therefore risk not reaching critical mass. If Sendmail doesnt implement Sender ID directly in its MTA [Mail Transfer Agent], its inevitable that Sender ID wont get used as widely as it would otherwise." In addition, he said that since "Microsoft has failed to meet the IETFs deadline for full disclosure of the licensing terms and applicable patent details, the momentum of opinion seems to be that Microsofts IP will be dropped from the standard, meaning that the IETF will standardize on a tweaked version of the original SPF proposal." Allman also isnt optimistic about Microsoft making Sender ID open-source friendly. "Its pretty clear that its going to take an act of whatever deity Microsoft worships in order to get them to back down on the sublicensing issue. They made it absolutely clear to us that they were not even going to consider changing this, and the legal folks made it further clear that they would rather see Sender ID die than back down." Still, there are efforts still afoot within both Microsoft and the open-source community to make Sender ID acceptable to the IETF and the open-source community, so its possible that Microsoft may yet change its Sender ID licensing requirements. Microsoft did not respond to requests for comment. Check out eWEEK.coms Linux & Open Source Center for the latest open-source news, reviews and analysis.