Attempts to fight spam by identifying e-mails have hit problems over Microsoft's involvement in the process.
Identifying where e-mail comes from could thwart spammers
The Internet Engineering Task Force, an international standards body, has rejected Microsoft's contribution to the so-called Sender ID proposal.
The proposal, which would identify where e-mail has come from, could lead to better filters to siphon out spam.
But Microsoft's decision to impose restrictions on the use of the system has angered some.
The working group charged by the IETF with looking at the standard has decided that Microsoft's decision to keep a possible patent application secret was unacceptable.
It was also concerned with possible incompatibilities with open source software.
Microsoft remains hopeful that the Sender ID system can be kept alive.
"There's broad support for Sender ID technology and we encourage others to support and implement this technology so that together we can do more to tackle spam," the company said in a statement.
The idea of authenticating e-mail senders has been under discussion for several years as a way of tackling spammers who are increasingly dominating inboxes with junk.
Sender ID is the closest the industry has got to a standard but it is complicated because it incorporates two approaches to the technical problem of tracing and tracking where e-mail has come from.
Microsoft has contributed some of the design and subsequently wants anyone using the system to take out a licence.
Sender ID could allow users to build reliable filters, accepting spam only from proven sources
But spammers may find ways to fool any authentication
Microsoft's system of Purported Responsible Authority offers an algorithm to identify who wrote e-mail based on the headers
But the conditions associated with this licence are considered unacceptable by many.
It has also re-opened the battle between Microsoft and the open source community, with many unhappy that the company is staking its claim on Sender ID.
The fact that internet engineers have voted down Microsoft's proposals does not necessarily mean the end of Sender ID or Microsoft's involvement.
It could continue to push for its system to become the de facto standard or it could make its system available to the open source community.