Microsoft re-pitches anti-spam standard

The company advocates labelling emails with the sender's IP attached to make it more easily traced. Sender ID checks whether an email's sender matches the corresponding IP address. While it's easy to spoof an email address, it is harder to spoof an IP address.

Software developers and service providers can now use the technology without having to pay a licence fee to Microsoft.

Microsoft essentially promises not to sue any developers or distributors for using the technology.

The Sender ID technology requires domain owners to publish so-called Sender Policy Framework (SPF) records, a list of IP addresses used to send email. Microsoft claims about five million internet domains have adopted Sender ID. µ